I accidentally changed a user to superadministrator instead of author. Now I wanted to change this back but the grouplist was gone in the CB User manager. It simply stated superadministrator.

Where in the database can I change this back to author or normal user ?

You have to find his name in users and match the number that delegates authority to that of everyone else, Whhish I could help you but I have not had to do this yet! (Touch Wood)

After some trial and error I was able to get it back. I've changed data in 4 tables (don't remember which ones exactly).