To remove door knob, you only need a Phillips screwdriver and possibly a flat edge screwdriver, depending on your specific doorknob. The entire project only takes about 10 minutes, as long as you don’t have trouble with the screws.
Step 1 - Remove the Trim
The plate that's behind the door knob on both sides of the door is the trim. Unscrew the screws on the trim on each side of the door and remove those pieces.
Step 2 - Remove the Long Screws
With the trim gone, you'll be able to see the heads of the two long screws that hold the doorknob in place. Remove each of these.
Step 3 - Remove the Knobs
After these screws are out, you can pull the knobs apart and remove door knob from the door.
Step 4 - Remove the Lock
With the knobs gone, now remove the screws that hold the bolt in place.
Step 5 - Remove the Strike Plate if Necessary
If you'll be replacing the strike plate, which is the plate on the edge of the door that catches the lock as it's released, then remove the screws and pry this away from the door. In most cases, you can leave the strike plate in place, however, and it will work find with a new door knob.