Whenever you’ve configured WSUS client settings on a Windows device, you can only remove those settings by using Group Policy by setting them to ‘disabled’ or by removing the registry settings from the client.
In my situation I’ve chosen to use PowerShell to accomplish this task:
Remove-Item -Path 'HKLM:\Software\Policies\Microsoft\Windows\WindowsUpdate\*' -recurse -force
After this, delete the clients manually from the WSUS management console and you’re done 🙂
Now the client will revert back to using the online Windows Updates from Microsoft instead of your WSUS infrastructure.
Note: Make sure the settings to configure the WSUS client to use your WSUS infrastructure are not applied anymore before executing the script!