Update plan-connect-userprincipalname.md

Extending the note on UPN recalculation to include add/removal of custom domain as a trigger to proxycalc task. Adding link to existing extended explanation about these activities and how to self-serve and troubleshoot from the audit logs.

Author: Renato Vieira

articles/active-directory/hybrid/plan-connect-userprincipalname.md

@@ -76,6 +76,8 @@ When the updates to a user object are synchronized to the Azure AD Tenant, Azure
 >Azure AD recalculates the UserPrincipalName attribute value only in case an update to the on-premises UserPrincipalName attribute/Alternate login ID value is synchronized to the Azure AD Tenant. 
 >
 >Whenever Azure AD recalculates the UserPrincipalName attribute, it also recalculates the MOERA. 
+>
+>In case of verified domain change, Azure AD also recalculates the UserPrincipalName attribute. For more information, see [Troubleshoot: Audit data on verified domain change](https://docs.microsoft.com/en-us/azure/active-directory/reports-monitoring/troubleshoot-audit-data-verified-domain)
 
 ## UPN scenarios
 The following are example scenarios of how the UPN is calculated based on the given scenario.
@@ -174,4 +176,4 @@ Azure AD Tenant user object:
 
 ## Next Steps
 - [Integrate your on-premises directories with Azure Active Directory](whatis-hybrid-identity.md)
-- [Custom installation of Azure AD Connect](how-to-connect-install-custom.md)
+- [Custom installation of Azure AD Connect](how-to-connect-install-custom.md)