I found that I can use a regular key to push the pin on the left side to allow the door to slide down. The left side has the track for guiding the door into the closed, mirror, and open positions. I first pushed the door up as far as it can go, then pushed the pin toward me with the key, then lightly pulled the door to the open position, and that did it. The key just pushes the pin toward follow the track to open the door.