diff --git a/Changelog.rst b/Changelog.rst
index a1589f3cfb..2bee5eaa55 100644
--- a/Changelog.rst
+++ b/Changelog.rst
@@ -1,3 +1,14 @@
+Version NEXTVERSION
+--------------
+
+**2025-??-??**
+
+* New methods to allow changing units in a chain: `cf.Field.to_units`,
+  `cf.Data.to_units`
+  (https://github.com/NCAS-CMS/cf-python/issues/874)
+
+----
+
 Version 3.18.0
 --------------
 
diff --git a/cf/data/data.py b/cf/data/data.py
index 7fcd08024f..cf4b50c167 100644
--- a/cf/data/data.py
+++ b/cf/data/data.py
@@ -5651,13 +5651,21 @@ def change_calendar(self, calendar, inplace=False, i=False):
     @_deprecated_kwarg_check("i", version="3.0.0", removed_at="4.0.0")
     @_inplace_enabled(default=False)
     def override_units(self, units, inplace=False, i=False):
-        """Override the data array units.
+        """Override the units.
 
-        Not to be confused with setting the `Units` attribute to units
-        which are equivalent to the original units. This is different
-        because in this case the new units need not be equivalent to the
-        original ones and the data array elements will not be changed to
-        reflect the new units.
+        The new units need not be equivalent to the original ones, and
+        the data array elements will not be changed to reflect the new
+        units. Therefore, this method should only be used when it is
+        known that the data array values are correct but the units
+        have incorrectly encoded.
+
+        Not to be confused with changing to equivalent units with the
+        `to_units` method or the `Units`, `units`, or `calendar`
+        attributes. These approaches also convert the data to have the
+        new units.
+
+        .. seealso:: `override_calendar`, `to_units`, `Units`,
+                     `units`, `calendar`
 
         :Parameters:
 
@@ -5695,13 +5703,20 @@ def override_units(self, units, inplace=False, i=False):
     @_deprecated_kwarg_check("i", version="3.0.0", removed_at="4.0.0")
     @_inplace_enabled(default=False)
     def override_calendar(self, calendar, inplace=False, i=False):
-        """Override the calendar of the data array elements.
+        """Override the calendar of date-time units.
+
+        The new calendar need not be equivalent to the original one,
+        and the data array elements will not be changed to reflect the
+        new calendar. Therefore, this method should only be used when
+        it is known that the data array values are correct but the
+        calendar has been incorrectly encoded.
+
+        Not to be confused with changing to an equivalent calendar
+        with the `to_units` method or the `Units` or `calendar`
+        attributes.
 
-        Not to be confused with using the `change_calendar` method or
-        setting the `d.Units.calendar`. `override_calendar` is different
-        because the new calendar need not be equivalent to the original
-        ones and the data array elements will not be changed to reflect
-        the new units.
+        .. seealso:: `override_units`, `to_units`, `Units`, `units`,
+                     `calendar`
 
         :Parameters:
 
@@ -7365,6 +7380,57 @@ def to_memory(self):
             "Consider using 'Data.persist' instead."
         )
 
+    @_inplace_enabled(default=False)
+    def to_units(self, units, inplace=False):
+        """Change the data array units.
+
+        Changing the units causes the data values to be changed
+        to match the new units, therefore the new units must be
+        equivalent to the existing ones.
+
+        Not to be confused with overriding the units with
+        `override_units`
+
+        .. versionadded:: NEXTVERSION
+
+        .. seealso:: `override_units`, `override_calendar`, `Units`,
+                     `units`, `calendar`
+
+        :Parameters:
+
+            units: `str` or `Units`
+                The new units for the data array.
+
+            {{inplace: `bool`, optional}}
+
+        :Returns:
+
+            `Data` or `None`
+                The new data, or `None` if the operation was in-place.
+
+        **Examples**
+
+        >>> d = cf.Data([1, 2], 'km')
+        >>> e = d.to_units('metre')
+        >>> print(e.Units)
+        'metre'
+        >>> print(e.array)
+        [1000. 2000.]
+        >>> e.to_units('miles', inplace=True)
+        >>> print(e.Units)
+        'miles'
+        >>> print(e.array)
+        [0.62137119 1.24274238]
+        >>> e.to_units('degC')
+        Traceback (most recent call last)
+            ...
+        ValueError: Can't set Units to <Units: degC> that are not equivalent to the current units <Units: miles>. Consider using the override_units method instead.
+
+        """
+        d = _inplace_enabled_define_and_cleanup(self)
+        d.Units = self._Units_class(units)
+        return d
+
     @_deprecated_kwarg_check("i", version="3.0.0", removed_at="4.0.0")
     @_inplace_enabled(default=False)
     def trunc(self, inplace=False, i=False):
diff --git a/cf/mixin/propertiesdata.py b/cf/mixin/propertiesdata.py
index 158bd2dc17..e58ee361c9 100644
--- a/cf/mixin/propertiesdata.py
+++ b/cf/mixin/propertiesdata.py
@@ -4431,6 +4431,71 @@ def to_dask_array(self):
 
         return data.to_dask_array()
 
+    @_inplace_enabled(default=False)
+    def to_units(self, units, inplace=False):
+        """Change the data array units.
+
+        Changing the units causes the data values to be changed
+        to match the new units, therefore the new units must be
+        equivalent to the existing ones.
+
+        Not to be confused with overriding the units with
+        `override_units`
+
+        .. versionadded:: NEXTVERSION
+
+        .. seealso:: `override_units`, `override_calendar`, `Units`,
+                     `units`, `calendar`
+
+        :Parameters:
+
+            units: `str` or `Units`
+                The new units for the data array.
+
+            {{inplace: `bool`, optional}}
+
+        :Returns:
+
+            `{{class}}` or `None`
+                The construct with data converted to the new units, or
+                `None` if the operation was in-place.
+
+        **Examples**
+
+        >>> print(f.Units)
+        'km'
+        >>> print(f.array)
+        [1 2]
+        >>> g = f.to_units('metre')
+        >>> print(g.Units)
+        'metre'
+        >>> print(g.array)
+        [1000. 2000.]
+        >>> g.to_units('miles', inplace=True)
+        >>> print(g.array)
+        [0.62137119 1.24274238]
+        >>> g.to_units('degC')
+        Traceback (most recent call last)
+            ...
+        ValueError: Can't set Units to <Units: degC> that are not equivalent to the current units <Units: miles>. Consider using the override_units method instead.
+
+        """
+        f = _inplace_enabled_define_and_cleanup(self)
+
+        data = f.get_data(None)
+        if data is not None:
+            data.to_units(units, inplace=True)
+            f.set_data(data, copy=False)
+        else:
+            f._custom["Units"] = Units(units)
+
+        # Change the Units on the period
+        period = f.period()
+        if period is not None:
+            f.period(period=period.to_units(units))
+
+        return f
+
     @_deprecated_kwarg_check("i", version="3.0.0", removed_at="4.0.0")
     @_inplace_enabled(default=False)
     def trunc(self, inplace=False, i=False):
@@ -4954,15 +5019,16 @@ def override_calendar(self, calendar, inplace=False, i=False):
 
         The new calendar need not be equivalent to the original one,
         and the data array elements will not be changed to reflect the
-        new units. Therefore, this method should only be used when it
-        is known that the data array values are correct but the
+        new calendar. Therefore, this method should only be used when
+        it is known that the data array values are correct but the
         calendar has been incorrectly encoded.
 
-        Not to be confused with setting the `calendar` or `Units`
-        attributes to a calendar which is equivalent to the original
-        calendar
+        Not to be confused with changing to an equivalent calendar
+        with the `to_units` method or the `Units` or `calendar`
+        attributes.
 
-        .. seealso:: `calendar`, `override_units`, `units`, `Units`
+        .. seealso:: `override_units`, `to_units`, `units`, `Units`,
+                     `calendar`
 
         :Parameters:
 
@@ -4976,13 +5042,20 @@ def override_calendar(self, calendar, inplace=False, i=False):
         :Returns:
 
             `{{class}}` or `None`
-                TODO
+                The construct with data converted to the new units, or
+                `None` if the operation was in-place.
 
         **Examples**
 
-        TODO
-
+        >>> f.Units
+        <Units: days since 2020-02-28>
+        >>> print(f.array)
+        1
         >>> g = f.override_calendar('noleap')
+        >>> g.Units
+        <Units: days since 2020-02-28 noleap>
+        >>> print(f.array)
+        1
 
         """
         v = _inplace_enabled_define_and_cleanup(self)
@@ -5015,11 +5088,13 @@ def override_units(self, units, inplace=False, i=False):
         known that the data array values are correct but the units
         have incorrectly encoded.
 
-        Not to be confused with setting the `units` or `Units`
-        attributes to units which are equivalent to the original
-        units.
+        Not to be confused with changing to equivalent units with the
+        `to_units` method or the `Units`, `units`, or `calendar`
+        attributes. These approaches also convert the data to have the
+        new units.
 
-        .. seealso:: `calendar`, `override_calendar`, `units`, `Units`
+        .. seealso:: `override_calendar`, `to_units`, `units`,
+                     `Units`,`calendar`
 
         :Parameters:
 
@@ -5033,8 +5108,8 @@ def override_units(self, units, inplace=False, i=False):
         :Returns:
 
             `{{class}}` or `None`
-
-        TODO
+                The construct with data converted to the new units, or
+                `None` if the operation was in-place.
 
         **Examples**
 
diff --git a/cf/mixin/propertiesdatabounds.py b/cf/mixin/propertiesdatabounds.py
index 21e8b9f803..33c2df6d40 100644
--- a/cf/mixin/propertiesdatabounds.py
+++ b/cf/mixin/propertiesdatabounds.py
@@ -2182,17 +2182,18 @@ def match_by_identity(self, *identities):
     def override_calendar(self, calendar, inplace=False, i=False):
         """Override the calendar of date-time units.
 
-        The new calendar **need not** be equivalent to the original one
-        and the data array elements will not be changed to reflect the new
-        units. Therefore, this method should only be used when it is known
-        that the data array values are correct but the calendar has been
-        incorrectly encoded.
+        The new calendar need not be equivalent to the original one,
+        and the data array elements will not be changed to reflect the
+        new calendar. Therefore, this method should only be used when
+        it is known that the data array values are correct but the
+        calendar has been incorrectly encoded.
 
-        Not to be confused with setting the `calendar` or `Units`
-        attributes to a calendar which is equivalent to the original
-        calendar
+        Not to be confused with changing to an equivalent calendar
+        with the `to_units` method or the `Units` or `calendar`
+        attributes.
 
-        .. seealso:: `calendar`, `override_units`, `units`, `Units`
+        .. seealso:: `override_units`, `to_units`, `Units`, `units`,
+                     `calendar`
 
         :Parameters:
 
@@ -2205,13 +2206,21 @@ def override_calendar(self, calendar, inplace=False, i=False):
 
         :Returns:
 
-        TODO
+            `{{class}}` or `None`
+                The construct with data converted to the new units, or
+                `None` if the operation was in-place.
 
         **Examples**
 
-        TODO
-
+        >>> f.Units
+        <Units: days since 2020-02-28>
+        >>> print(f.array)
+        1
         >>> g = f.override_calendar('noleap')
+        >>> g.Units
+        <Units: days since 2020-02-28 noleap>
+        >>> print(f.array)
+        1
 
         """
         return self._apply_superclass_data_oper(
@@ -2229,16 +2238,19 @@ def override_calendar(self, calendar, inplace=False, i=False):
     def override_units(self, units, inplace=False, i=False):
         """Override the units.
 
-        The new units need not be equivalent to the original ones, and the
-        data array elements will not be changed to reflect the new
-        units. Therefore, this method should only be used when it is known
-        that the data array values are correct but the units have
-        incorrectly encoded.
+        The new units need not be equivalent to the original ones, and
+        the data array elements will not be changed to reflect the new
+        units. Therefore, this method should only be used when it is
+        known that the data array values are correct but the units
+        have incorrectly encoded.
 
-        Not to be confused with setting the `units` or `Units` attribute
-        to units which are equivalent to the original units.
+        Not to be confused with changing to equivalent units with the
+        `to_units` method or the `Units`, `units`, or `calendar`
+        attributes. These approaches also convert the data values to conform
+        with the new units.
 
-        .. seealso:: `calendar`, `override_calendar`, `units`, `Units`
+        .. seealso:: `override_calendar`, `to_units`, `Units`,
+                     `units`, `calendar`
 
         :Parameters:
 
@@ -2251,7 +2263,9 @@ def override_units(self, units, inplace=False, i=False):
 
         :Returns:
 
-                TODO
+            `{{class}}` or `None`
+                The construct with data converted to the new units, or
+                `None` if the operation was in-place.
 
         **Examples**
 
@@ -3306,6 +3320,64 @@ def log(self, base=None, bounds=True, inplace=False, i=False):
             i=i,
         )
 
+    @_inplace_enabled(default=False)
+    def to_units(self, units, inplace=False):
+        """Change the data array units.
+
+        Changing the units causes the data values to be changed
+        to match the new units, therefore the new units must be
+        equivalent to the existing ones.
+
+        Not to be confused with overriding the units with
+        `override_units`
+
+        .. versionadded:: NEXTVERSION
+
+        .. seealso:: `override_units`, `override_calendar`, `Units`,
+                     `units`, `calendar`
+
+        :Parameters:
+
+            units: `str` or `Units`
+                The new units for the data array.
+
+            {{inplace: `bool`, optional}}
+
+        :Returns:
+
+            `{{class}}` or `None`
+                The construct with data converted to the new units, or
+                `None` if the operation was in-place.
+
+        **Examples**
+
+        >>> print(f.Units)
+        'km'
+        >>> print(f.array)
+        [1 2]
+        >>> g = f.to_units('metre')
+        >>> print(g.Units)
+        'metre'
+        >>> print(g.array)
+        [1000. 2000.]
+        >>> g.to_units('miles', inplace=True)
+        >>> print(g.array)
+        [0.62137119 1.24274238]
+        >>> g.to_units('degC')
+        Traceback (most recent call last)
+            ...
+        ValueError: Can't set Units to <Units: degC> that are not equivalent to the current units <Units: miles>. Consider using the override_units method instead.
+
+        """
+        return self._apply_superclass_data_oper(
+            _inplace_enabled_define_and_cleanup(self),
+            "to_units",
+            (units,),
+            bounds=True,
+            interior_ring=False,
+            inplace=inplace,
+        )
+
     @_deprecated_kwarg_check("i", version="3.0.0", removed_at="4.0.0")
     @_inplace_enabled(default=False)
     def trunc(self, bounds=True, inplace=False, i=False):
diff --git a/cf/test/test_Data.py b/cf/test/test_Data.py
index 026ad9e2c8..5918fb79b6 100644
--- a/cf/test/test_Data.py
+++ b/cf/test/test_Data.py
@@ -4684,6 +4684,23 @@ def test_Data_collapse_axes_hdf_chunks(self):
         self.assertEqual(e._axes, d._axes[1:])
         self.assertEqual(e.nc_dataset_chunksizes(), chunks)
 
+    def test_Data_to_units(self):
+        """Test cf.Data.to_units."""
+        d = cf.Data([1, 2], "km")
+        e = d.to_units("m")
+
+        self.assertIsInstance(e, d.__class__)
+        self.assertEqual(e.Units, cf.Units("m"))
+        self.assertTrue(np.allclose(e.array, [1000.0, 2000.0]))
+
+        self.assertIsNone(e.to_units("miles", inplace=True))
+        self.assertEqual(e.Units, cf.Units("miles"))
+        self.assertTrue(np.allclose(e.array, [0.62137119, 1.24274238]))
+
+        # Non-equivalent units
+        with self.assertRaises(ValueError):
+            e.to_units("degC")
+
 
 if __name__ == "__main__":
     print("Run date:", datetime.datetime.now())
diff --git a/cf/test/test_DimensionCoordinate.py b/cf/test/test_DimensionCoordinate.py
index 3fbcb22a92..c727e2d1e0 100644
--- a/cf/test/test_DimensionCoordinate.py
+++ b/cf/test/test_DimensionCoordinate.py
@@ -840,6 +840,28 @@ def test_DimensionCoordinate_direction(self):
         d._custom["direction"] = None
         self.assertTrue(d[0].direction())
 
+    def test_DimensionCoordinate_to_units(self):
+        """Test DimensionCoordinate.to_units."""
+        f = cf.example_field(0)
+        d = f.dimension_coordinate("X")
+        d = d[:2]
+        self.assertEqual(d.period().Units, cf.Units("degrees_east"))
+
+        e = d.to_units("rad")
+        self.assertIsInstance(e, d.__class__)
+        self.assertEqual(e.Units, cf.Units("rad"))
+        self.assertTrue(np.allclose(e.array, [0.39269908, 1.17809725]))
+        self.assertEqual(e.period().Units, cf.Units("rad"))
+
+        self.assertIsNone(e.to_units("degrees_east", inplace=True))
+        self.assertEqual(e.Units, cf.Units("degrees_east"))
+        self.assertTrue(np.allclose(e.array, [22.5, 67.5]))
+        self.assertTrue(np.allclose(e.period().array, d.period().array))
+
+        # Non-equivalent units
+        with self.assertRaises(ValueError):
+            e.to_units("degC")
+
 
 if __name__ == "__main__":
     print("Run date:", datetime.datetime.now())
diff --git a/cf/test/test_Field.py b/cf/test/test_Field.py
index 03f87c7a46..3e0f74979f 100644
--- a/cf/test/test_Field.py
+++ b/cf/test/test_Field.py
@@ -3035,6 +3035,24 @@ def test_Field_filled(self):
         self.assertEqual(values[0], -999)
         self.assertEqual(counts[0], 5)
 
+    def test_Field_to_units(self):
+        """Test Field.to_units."""
+        f = cf.example_field(0)
+        f = f[0, :2]
+
+        g = f.to_units("g/kg")
+        self.assertIsInstance(f, g.__class__)
+        self.assertEqual(g.Units, cf.Units("g/kg"))
+        self.assertTrue(np.allclose(g.array, [7.0, 34.0]))
+
+        self.assertIsNone(g.to_units("1", inplace=True))
+        self.assertEqual(g.Units, cf.Units("1"))
+        self.assertTrue(np.allclose(g.array, [0.007, 0.034]))
+
+        # Non-equivalent units
+        with self.assertRaises(ValueError):
+            g.to_units("degC")
+
 
 if __name__ == "__main__":
     print("Run date:", datetime.datetime.now())
diff --git a/docs/source/class/cf.AuxiliaryCoordinate.rst b/docs/source/class/cf.AuxiliaryCoordinate.rst
index 6216de643f..2e7c8bf0b0 100644
--- a/docs/source/class/cf.AuxiliaryCoordinate.rst
+++ b/docs/source/class/cf.AuxiliaryCoordinate.rst
@@ -192,6 +192,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.AuxiliaryCoordinate.to_units
    ~cf.AuxiliaryCoordinate.override_units
    ~cf.AuxiliaryCoordinate.override_calendar
 
diff --git a/docs/source/class/cf.Bounds.rst b/docs/source/class/cf.Bounds.rst
index 27a29b1010..4e1601b16a 100644
--- a/docs/source/class/cf.Bounds.rst
+++ b/docs/source/class/cf.Bounds.rst
@@ -106,6 +106,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.Bounds.to_units
    ~cf.Bounds.override_units
    ~cf.Bounds.override_calendar
 
diff --git a/docs/source/class/cf.CellConnectivity.rst b/docs/source/class/cf.CellConnectivity.rst
index 791479de51..b7e4db1270 100644
--- a/docs/source/class/cf.CellConnectivity.rst
+++ b/docs/source/class/cf.CellConnectivity.rst
@@ -129,6 +129,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.CellConnectivity.to_units
    ~cf.CellConnectivity.override_units
    ~cf.CellConnectivity.override_calendar
 
diff --git a/docs/source/class/cf.CellMeasure.rst b/docs/source/class/cf.CellMeasure.rst
index 8e61434557..f10d0e2f6b 100644
--- a/docs/source/class/cf.CellMeasure.rst
+++ b/docs/source/class/cf.CellMeasure.rst
@@ -129,6 +129,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.CellMeasure.to_units
    ~cf.CellMeasure.override_units
    ~cf.CellMeasure.override_calendar
 
diff --git a/docs/source/class/cf.Count.rst b/docs/source/class/cf.Count.rst
index 27d04c6cf0..8431fb1c45 100644
--- a/docs/source/class/cf.Count.rst
+++ b/docs/source/class/cf.Count.rst
@@ -102,6 +102,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.Count.to_units
    ~cf.Count.override_units
    ~cf.Count.override_calendar
 
diff --git a/docs/source/class/cf.Data.rst b/docs/source/class/cf.Data.rst
index 488ea75df8..b89f262de9 100644
--- a/docs/source/class/cf.Data.rst
+++ b/docs/source/class/cf.Data.rst
@@ -42,6 +42,7 @@ Units
    ~cf.Data.get_units
    ~cf.Data.has_units
    ~cf.Data.set_units
+   ~cf.Data.to_units
    ~cf.Data.override_units
    ~cf.Data.del_calendar
    ~cf.Data.get_calendar
diff --git a/docs/source/class/cf.DimensionCoordinate.rst b/docs/source/class/cf.DimensionCoordinate.rst
index 7defc250e6..1878f43de2 100644
--- a/docs/source/class/cf.DimensionCoordinate.rst
+++ b/docs/source/class/cf.DimensionCoordinate.rst
@@ -196,6 +196,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.DimensionCoordinate.to_units
    ~cf.DimensionCoordinate.override_units
    ~cf.DimensionCoordinate.override_calendar
 
diff --git a/docs/source/class/cf.DomainAncillary.rst b/docs/source/class/cf.DomainAncillary.rst
index 61d8f795e6..4d4edba246 100644
--- a/docs/source/class/cf.DomainAncillary.rst
+++ b/docs/source/class/cf.DomainAncillary.rst
@@ -175,6 +175,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.DomainAncillary.to_units
    ~cf.DomainAncillary.override_units
    ~cf.DomainAncillary.override_calendar
 
diff --git a/docs/source/class/cf.DomainTopology.rst b/docs/source/class/cf.DomainTopology.rst
index a651bd72ad..2002c849d1 100644
--- a/docs/source/class/cf.DomainTopology.rst
+++ b/docs/source/class/cf.DomainTopology.rst
@@ -130,6 +130,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.DomainTopology.to_units
    ~cf.DomainTopology.override_units
    ~cf.DomainTopology.override_calendar
 
diff --git a/docs/source/class/cf.Field.rst b/docs/source/class/cf.Field.rst
index 8183b61434..1c307f362e 100644
--- a/docs/source/class/cf.Field.rst
+++ b/docs/source/class/cf.Field.rst
@@ -122,6 +122,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.Field.to_units
    ~cf.Field.override_units
    ~cf.Field.override_calendar
    
diff --git a/docs/source/class/cf.FieldAncillary.rst b/docs/source/class/cf.FieldAncillary.rst
index 62bdbb2381..34271875f6 100644
--- a/docs/source/class/cf.FieldAncillary.rst
+++ b/docs/source/class/cf.FieldAncillary.rst
@@ -105,6 +105,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.FieldAncillary.to_units
    ~cf.FieldAncillary.override_units
    ~cf.FieldAncillary.override_calendar
 
diff --git a/docs/source/class/cf.Index.rst b/docs/source/class/cf.Index.rst
index 2717ebba13..c8246f1c0e 100644
--- a/docs/source/class/cf.Index.rst
+++ b/docs/source/class/cf.Index.rst
@@ -102,6 +102,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.Index.to_units
    ~cf.Index.override_units
    ~cf.Index.override_calendar
 
diff --git a/docs/source/class/cf.List.rst b/docs/source/class/cf.List.rst
index d96f2f48a5..51dde4b8c9 100644
--- a/docs/source/class/cf.List.rst
+++ b/docs/source/class/cf.List.rst
@@ -102,6 +102,7 @@ Units
    :toctree: ../method/
    :template: method.rst
 
+   ~cf.List.to_units
    ~cf.List.override_units
    ~cf.List.override_calendar