I've been trying to move some event registrations from one contact to another. Noting form the admin screen that there is a 'Cancel or Transfer' link available when viewing event registrations from the contact's 'Events' tab, I gave it a try. Sure enough I got a pop-up asking for the name and email address of the contact to transfer to, and on submitting that it seemed to work, although I then got taken to the event registration form oddly.
Trying the same trick again for another contact record, and all I get now is a message saying "Sorry, You cannot transfer or cancel your registration for as you are not currently registered for this event." which seems pretty weird given that a) I'm logged in as an administrator and b) that I'd just done exactly this with another contact record.
Looking at https://issues.civicrm.org/jira/browse/CRM-20879 the impression there, albeit an old issue, is that enabling admins to do this is not yet built.
What's the current state of play on this? (running 5.10.4 at the time of writing)