Commercial door knobs are often designed much like the door knobs found in old homes. Both of the knobs were designed to have no exterior screws holding the base at the plate of the knob to the door. Instead, the screws are underneath the plate which requires you to pop the plate off to remove the door knob. This is one of the fundamental differences in changing a commercial door knob as opposed to a residential knob. The removal and installation of a commercial door knob will take you approximately an hour and requires a few basic tools.
Use an electric screwdriver or a drill to remove the two screws in the latch plate. The latch plate is the rectangular plate located on the inside of the door. Take a corner of the putty knife and pry the latch plate from the door. Discard the plate.
Locate the slot on the base of the door knob plate. Look for a small opening between the door and the plate on the right or left side. Slide a corner of your putty knife into the slot and turn your wrist towards the door knob. The plate should loosen and pop free.
Pull the plate towards the knob so you can access the hardware it covers. Underneath the plate is called the rose. The rose will have a very small opening on the side similar to the plate. Stick a slender object such as a small screwdriver or an unfolded paperclip inside the opening. Pull on the door knob while pushing the screwdriver or paperclip down into the opening. Depress the small wire to release the knob; it may take a couple of tries. Once you release the wire, the rose will come free of the door.
Pull the knob off of the door and set aside. Slide the plate and the rose off of the door. Unscrew the screws that are on the baseplate underneath the rose to loosen the knob on the other side of the door. Slide it out of the door.
Slide the latch mechanism that is attached to the latch plate into the side of the door. Place the screws that came with the knob kit into the holes. Twist the screws by hand three to four times to temporarily secure the latch and the latch plate. Tighten these screws down later.
Take the knob that includes the cylinder and slide it into the hole in the door. Line it up to go through the latch mechanism. It has been lined up correctly if you turn the knob and the latch moves.
Place your hand on the knob and slide the baseplate onto the end of the cylinder that is protruding from the hole on the interior of the door.
Screw the screws into the holes of the baseplate with the drill or electric screwdriver. Slide the rose over the baseplate and press it until it clicks into place.
Thread the door knob through the plate. Slide the knob onto the cylinder and on top of the rose. Click the plate into the rose to secure. Test the knob by turning it to see if the latch still moves.
Tighten the screws in the latch plate with the screwdriver or drill.