Despite what some homeowners may think, you can rekey your own deadbolts rather than hiring a locksmith to do the work. If you need to rekey multiple deadbolt locks, you will save even more by doing the work yourself. Go to a home improvement store to purchase a lock rekeying kit, which will come with almost everything you need to complete the job. Once you rekey the lock, have copies made of the key that comes with the kit.
Undo the screws on the plate attached to the interior side of the door, and then remove the plate. Undo the screws on the plate below the first plate and remove the second plate as well.
Remove the assembly on the exterior side of the door, since you have already removed the screws holding it in place. Push on the front of the lock cylinder to push it out of the back of its housing.
Clamp the retainer ring tool onto the lock cylinder, just behind the retainer ring. Twist the tool clockwise to remove the retainer ring and set it aside.
Place the old key in the lock mechanism and turn it right a quarter rotation. Push on the back of the cylinder plug with a plug follower while you pull on the old key. Leave the plug follower in the lock cylinder.
Remove the old key from the plug, then rotate the plug and dump out the pins. Use tweezers to install the new, color-coded pins in the order specified in the lock rekeying kit's instruction booklet. Reassemble the deadbolt lock assembly in the reverse order you took it apart.