You want to roll back to a previous cumulative update installed on your machine but you do not want to completely re-install the SDL application.

To uninstall the last Cumulative Update applied to SDL Trados Studio or to SDL MultiTerm Desktop perform the below steps which apply for Windows 7, Windows 8 and Windows 10:

1. Click on Start > Control Panel > Go to Programs > Programs and Features > View installed updates
2. Scroll down until you find the Cumulative Update that you want to uninstall
3. Right-click on it and select Uninstall

After the uninstall process is complete press F5 to refresh the installed updates list and check what the last Cumulative Update is. It should be the one previous to the one you just uninstalled.
 

You can uninstall just the last Cumulative Update from Windows Control Panel.