The instructions included are mostly correct. That said, as this is a ZigBee device, it doesn't have to be unpaired, but it has to be reset for it to be able to be paired again.
To reset the key fob, press and hold the star button, while it's being pressed, press the unlock/disarm button for 10 seconds. After 10 seconds, keep holding the star button pressed, but release the unlock/disarm button and the key fob will reset.
To pair the key fob, press the star button, then quickly press the lock/arm all button for less than 1 second and the key fob should go into pairing mode.
I've updated the instructions on the Wiki as well.