Bought a replacement entry lever door knob for the 2 year old one that periodically would go back to locked condition  after unlocking using the lever.  This was the only one out of the original 8.  I didn't have a key to get back in, letting our doog out early in the morning.  I was the only one home at the time, so I broke the lever off and was able to regain access to my home.  I made an extra set of keys and put back the hid out key as well.  It was a breeze replacing the lock set, only 2 screws and lined up the two pieces.