A cam lock is used for a drawer just like a file cabinet. A metal tab that releases a drawer from the drawer cavity is turned by a key cylinder. If you want to change a lock or your key is missing, you will have to remove the drawer lock you have now. There are different ways to remove a drawer locks based on how the lock is secured to the drawer. Some drawer locks are secured by screws, while others are secured by clips.
Open your drawer and check the back of the lock and you can see a back plate with two or four screws.
You need to move the lock tab from the retaining screw first by inserting the key into the lock cylinder and then counterclockwise turning the key. You’ll have to use a pair of vise grips if your key is missing.
Use a Phillips-head screwdriver to remove the screws. The back of the lock should be pulled away from the cylinder and then remove the lock cylinder from the drawer.
Find the C-clip which secures the lock to the drawer. Use a flat-head screwdriver to remove the C-clip if there are no screws. The lock bolt tab should be pulled off the rear of the lock and the cylinder should be removed from the drawer.