Board Thread:Support Requests - Designing Your Wikia/@comment-24065667-20160603093159/@comment-5007040-20160603121932

AmonFatalis wrote: You can request a buraucrat demotion via Special:Contact. There also need to be some demote thread about that on which the community can vote for demoting.

However, if they say they aren't going to contribute anymore, did you ask them to just demote them by themselves? And also, if they're not going to the wiki anymore, they won't do anything with the rights. No problems at all to add new ones then I think :)