Your latch is broken and you're locked out. What to do? First, take a plastic card or cut a piece of plastic bottle and insert it between the door and the frame. Next, you're going to want to find the source of the breakage. Check the alignment of the latch and strike plate. If it's unaligned, loosen the strike plate screws and shift it slightly. You can also file the slot in the strike plate a bit so that it will receive the latch. For a more than ⅛-inch misalignment, remove the strike plate, extend the mortise higher or lower, replace the plate and fill the gap at the top or bottom with wood putty.
If all else fails, you may need to remove the doorknob altogether. This can be done with a screwdriver (Flat or Phillips), an Allen Wrench and a paper clip or firm wire. Keep in mind that if your latch is completely broken, you can purchase a new latch at a hardware or locksmiths store and install it in the same location.
Remove the Knob
First and foremost, ensure your door is unlocked when removing the knob. Begin by examining the lock side of the doorknob and look for a tiny slot or hole. These are the detent access holes. If you don't see it, check for a recessed screw that you'll loosen with an Allen wrench.
How you release the knob depends on how it's fastened. For a slot, insert the flat-head screwdriver and push the detent to release the knob. For a small hole, use a straightened paper clip or firm wire to spring it. For a recessed hex-head screw, turn it counterclockwise with an Allen wrench until the knob is released.
Remove the Rose
Next, remove the flat circular part behind the knob, called the rose. To remove the rose separately and expose the screws that hold the backing plate to the door, locate the thin slot in the seam between the plate and door, insert the tip of the flat-head screwdriver and take off the rose.
Remove the Screws
Using a Phillips head screwdriver, remove the screws that run from one backing plate to its opposite through the bore hole. These screws hold the knob and latch assembly together. Finally, remove the old knobs, backing plates, latch and spindle. Once these steps have been completed, you can replace the broken latch door knob with a new door knob.