Transferring a project from a group to a user

I have a “legacy” group of projects which were imported from older VCSs. Now that GitLab is set up and running, I’m adding some of the non-developer users and one of the things I need to do is transfer some of these projects to the users who own them.

It looks like, as an admin, I cannot transfer a project from a group to a user other than myself. No other users appear in the Transfer Project dropdown for selecting a name space.

I’d be surprised if this isn’t possible… so how am I actually supposed to go about it?