Sorry for the cross post, but I'm desperate. I bought the VESA mount from Apple and installed it with no problem. Now, a year or so later, I need to reattach the base to take the iMac to a presentation tomorrow but I can't figure out how to get the mount on the iMac to swivel back inwards. To lock it out, you use a supplied plastic card. The directions don't tell you how to reverse it.