Help to remove a mount.

Help please, I am sure I am being very stupid but I have bought a set of rings which arrived yesterday. I wanted to check that the mounts were ok so fitter the set to the camera and then added a lens.

Problem is I can remove the mount from the camera but not from the lens, any ideas please? There is a machine screw in the mount but pushing, pulling nor a wiggle seems to make and difference, sure it is operator error but can’t see past what I have already tried.

Mine has a little lever you push to release the lens. It is a bit stiff though. Can you upload some pics perhaps?

The locking pin needs to move back into the body of the tubes to allow the lens to be rotated and removed so you'll need to move/push/press/turn a lever/button to achieve that.

Thank you, Thank you, easy when you know how all I need do now is learn to use them.