Clarify sign off label requirements for reviewers

Author: dstrome

.github/workflows/resources/AutoLabelAssign-ContentLeadReviewNotice.md

@@ -1,7 +1,7 @@
 
 You've been added as a reviewer to this pull request because you're [listed](https://aka.ms/getaxonomy) as a Content Lead for the product area or feature covered by one or more articles in this PR.
 
-Before this PR can be merged, a Content Lead needs to add the **Sign off** label to it. Before you sign off a PR, confirm the following:
+Before this PR can be merged, a Content Lead needs to add the **Sign off** label to it. Only **one** of the listed reviewers needs to add the **Sign off** label. Before you sign off a PR, confirm the following:
 
 - Article content has been checked for technical accuracy.
 - There are no errors or warnings in build validation.
@@ -15,6 +15,8 @@ After you've confirmed the above, do the following to sign off:
 1. Select **Sign off** from the label list.
 1. Click away from the label list.
 
+![image](https://learn.microsoft.com/en-us/office/media/internal/sign-off-label.jpg)
+
 After you've signed off, our operations (PubOps) team will review the PR for issues that may impact formatting and the customer experience. If any changes are needed, they will return
 the PR to the submitter with required changes. After they've completed those changes, you need to sign off again.