If you want to pick a lock in order to unlock a door without a lock you will need some basic lock picking tools.
How to replace a door lock without a key.
Next put a new latch in and replace the door knob.
You can re key a lock like a pro at a fraction of the cost.
Re keying kits are available for most lock brands but they re not interchangeable.
The key pins correspond to specific groove cuts on a key and these are the main elements that are targeted in the attempt to unlock a door without a key via lock picking.
To change the lock on a regular door knob first use a screwdriver to remove the door knob and the old latch.
If these doors are locked it can be difficult to remove the lock and replace it with a unit that works.
Once you have the kit remove the lock cylinder from the door knob so you can change the pins inside.
If you are able to gain access to the interior of the room through a window or some other means this is usually the easiest way to remove the lock.
Alternatively you can buy a re keying kit for the lock you already have.