Shut off the power to the disposer at the circuit breaker box. Label the breaker so nobody turns it back on while you are working on the disposal.
Disconnect the pipe fitting from the food waste disposer using a pipe wrench. Insert a screwdriver into the retaining ring at the top of the disposer and turn it counter-clockwise to release the disposer from the drain opening.
Lower the disposer down to the sink cabinet bottom. Remove the wire nuts and disconnect the electrical wires from the disposer if it is hard-wired. If it is fitted with a plug, unplug the unit from the outlet.