Board Thread:General Discussion/@comment-39880442-20190707033304/@comment-34888194-20190707225040

Banning administrator won't stop them from editing; they can unban themselves. However, if you are a bureaucrat, you can directly demote the admin right instead of banning them, because administrator also have the ability to unban themselves.

Also, does the admin have issues themselves? You will need to be much more specific than that.