Read this and answer the question

Phase-two mode can only be activated by a key switch located inside the elevator on the centralized control panel. This mode was created for firefighters so that they may rescue people from a burning building. The phase-two key switch located on the COP has three positions: off, on, and hold. By turning phase two on, the firefighter enables the car to move. However, like independent-service mode, the car will not respond to a car call unless the firefighter manually pushes and holds the door close button. Once the elevator gets to the desired floor it will not open its doors unless the firefighter holds the door open button. This is in case the floor is burning and the firefighter can feel the heat and knows not to open the door. The firefighter must hold door open until the door is completely opened. If for any reason the firefighter wishes to leave the elevator, they will use the hold position on the key switch to make sure the elevator remains at that floor. If the firefighter wishes to return to the recall floor, they simply turn the key off and close the doors.

How is the Phase-two mode enabled?
Phase-two mode can only be activated by a key switch located inside the elevator on the centralized control panel