Turn off the water supply to the sink. Look underneath the cabinet for a lever on the main water pipe. Turn it to the off position.
Drain the faucets. Turn both faucets to the on position clearing any water out of the pipes.
Loosen the water pipe connectors with a pipe wrench. Go underneath the sink and loosen the connections for both the hot and cold water.
Loosen the sink connector. Locate the main drainpipe underneath the sink. Loosen the connector with a pipe wrench.
Remove the sink. If it is an undermount, pressing down from the top breaks the seal. If it is an overmount, press up from underneath the cabinet. You may need to hit it with a rubber mallet loosening the bond between the cabinet and the sink. Lift the sink free and place it aside.
Pry up the base cabinet’s bottom. Base cabinets are usually nailed into the flooring underneath. Insert a pry bar and pry up. Loosen the nails and work the cabinet free. The cabinet may also be nailed to the side and back wall. If so, pry these nails free. Remove the cabinet.