you only have to desolder the switches you want (and any LEDs and/or diodes if they are installed in the switches). Once desoldered, on the top side of the switch where it mounts to the plate, there are 2 tabs centered on the top and bottom edge of the switch that you press to dislodge it from the plate.
EDIT: and if there are diodes or LEDs, it may be easier to just clip them off rather than desoldering, unless you want to save them.