Delta faucets are designed with an outer handle, inner sleeve and cartridge assembly. This makes their removal fairly simple. The project takes only about an hour to complete, even if you have never done it before.
Close the main water valve or shut the valves running just to the Delta faucet you want to remove.
Find the handle screw along the base of the lever (in lever-handled Delta faucets) and underneath a small plastic tab on round-handled Delta faucets. Remove this screw with the 1/8-inch Allen wrench or a Phillips-head screwdriver. Models including the 622 use a Phillips-head screw instead of an Allen-head screw. If your faucet has a tab cover on the handle, take off the tab and remove the screw.
Slide off the handle and the round, chrome trim. Just pull it back and off the faucet head since it is not screwed on.
Loosen the nut that holds on the cartridge with the large pliers and completely unscrew it. It may be necessary to use a screwdriver and hammer to get this part off. Put the screwdriver head into the slots on top of the washer, then tap it lightly with the hammer. After it is loosened, remove this part. Grab the end of the cartridge and pull it out of the inside of the faucet.
Remove the trim screws (if any) from the trim piece and pull the trim piece off the wall. What remains is the housing for the faucet head. If you are replacing the Delta faucet, it will be installed into this part. If this a kitchen-style faucet, remove the base trim and disconnect the faucet from the pipes below by unscrewing the pipe washers with a small pipe wrench.