[ovirt-users] How to unlock disk images?

On one oVirt 4.3 farm I have three locked images I'd like to clear out. One is an ISO image, that somehow never completed the transfer due to a slow network. It's occupying little space, except in the GUI where it sticks out and irritates. I guess it would just be an update somewhere on the Postgress database to unlock it and have it deletable: But since the schema isn't documented, I'd rather ask here: How to I unlock the image? Two are left-overs from a snapshot that somehow never completed, one for the disk another for the RAM part. I don't know how my colleague managed to get into that state, but impatience/concurrency probably was a factor, a transient failure of a node could have been another. In any case the snapshot operation logically has been going on for weeks without any real activity, survived several restarts (after patches) of all nodes and the ME and shows no sign of disappearing voluntarily. Again, I'd assume that I need to clear out the snapshot job, unlock the images and then delete what's left. Some easy SQL and most likely a management engine restart afterwards... if you knew what you were doing (or there was an option in the GUI). So how do I list/delete snapshot jobs that aren't really running any more? And how do I unlock the images so I can delete them? Thanks for your help!