Multi-functional mortise lock

A multi-functional mortise lock that can be rapidly converted between different functions without opening the mortise lock case by installing blocking screws that extend through threaded blocking openings in a sidewall of the case and into blocking interference with moving components inside the case. The moving components include a lock/unlock lever, a latch retract lever and a spindle hub. The blocking screws are stored in threaded storage openings in the sidewall of the case. The sidewall of the case is marked adjacent to the threaded blocking openings and storage openings to identify functions that will be performed when the blocking screws are installed in one or more of the blocking openings.