Locate the release button on your Yale door knob, located on the neck of the knob.
Insert a small screwdriver or nail into the hole where the release button is located.
Press the release button, then remove the two screws from the top portion of door knob.
Pull off the door knob and remove it entirely from the door. Inspect the door knob for any damage, such as dents or cracks, and replace the door knob if necessary.
Place the door knob back onto the door, then reinsert the screw into the bottom portion of the door knob.
Reinsert the two screws into the door knob, then press the door knob in so that the release button locks.