Depending on how things are being run, you may need to change the UPN (User Principal Name) of individual users in your Active Directory. One reason for doing so is to use a hybrid local/Azure AD setup, where users use their email address for logging on to Azure, but their ordinary username to log on to the local domain. At any rate, here’s how to change the UPN of an individual user in Microsoft Active Directory:
- Search for the user in AD
- Right click and choose “Rename”
- Change “User logon name” to the desired logon name
- Click OK
That should see you sorted. Please note that changing User logon name will also change user logon name (pre-Windows 2000). If you need this to remain the same (e.g. because the user needs to be able to log in using their user name as well as the set UPN, you need to correct this.