DIYbanter - View Single Post - Need to remove the deadbolt from a locked door

writes:
I have a back door that has a deadbolt on it and is currently locked.
As you guessed it i have no key for it but i need to get it out so that
i can install a new one in its place. Any advise on how to get it out
would be really appreciated. Thank you.

Call a locksmith to come make you a key. He'll stick a blank key into
the cylinder, jiggle it back and forth so that it gets scratched where
there need to be notches, file down a bit where the scratches are, and
repeat until the key finally successfully opens the lock.