diff --git a/data-explorer/kusto/query/percentile-tdigest-function.md b/data-explorer/kusto/query/percentile-tdigest-function.md
index 73603694fd..d720b5496d 100644
--- a/data-explorer/kusto/query/percentile-tdigest-function.md
+++ b/data-explorer/kusto/query/percentile-tdigest-function.md
@@ -13,7 +13,7 @@ Calculates the percentile result from the `tdigest` results (which was generated
 
 ## Syntax
 
-`percentile_tdigest(`*expr*`,` *percentile1* `,` *typeLiteral*`)`
+`percentile_tdigest(`*expr*`,` *percentile* [`,` *typeLiteral*]`)`
 
 [!INCLUDE [syntax-conventions-note](../includes/syntax-conventions-note.md)]
 
@@ -21,7 +21,7 @@ Calculates the percentile result from the `tdigest` results (which was generated
 
 |Name|Type|Required|Description|
 |--|--|--|--|
-|*expr*| `string` | :heavy_check_mark:|An expression that was generated by [`tdigest`](tdigest-aggregation-function.md) or [tdigest_merge()](tdigest-merge-aggregation-function.md).|
+|*expr*| `dynamic` | :heavy_check_mark:|An expression that was generated by [`tdigest`](tdigest-aggregation-function.md) or [tdigest_merge()](tdigest-merge-aggregation-function.md).|
 |*percentile*| `real` | :heavy_check_mark:|The value that specifies the percentile.|
 |*typeLiteral*| `string` ||A type literal. If provided, the result set will be of this type. For example, `typeof(long)` will cast all results to type `long`.