Unthread and remove all the trim screws around the lock plate with a Phillips screwdriver.
Loosen and remove the edge plate trim screws with a Phillips screwdriver. Pull the edge plate trim from the door.
Pull both sides of the lock away from the door. If the lock is still attached, unthread and remove the edge plate screws from beneath the trim plate.
Pull the edge plate and bolt assembly from the door edge. Pull both sides of the lock away from the door.
Replace the lock pieces on the opposite sides of the door. Press until the two sides click together.
Replace the edge plate, screws and trim. Tighten the screws with a Phillips screwdriver.
Replace the lock trim and screws and test the lock.