Unlock the tailgate by pulling the locking pins out of each side lock. You will locate a pin on the left and right side of the tailgate. In most cases, the pins attach to chains to prevent you from losing them. As you remove the pins, hold the tailgate in an upright and closed position.
Tilt the tailgate open slightly to make it easier to slide the tailgate off the hinges.
Slide the tailgate to the left or to the right to slide the pins on the tailgate out of the hinges welded to the frame of the trailer. The tailgate will only slide one way. However, that way depends on the construction of the tailgate and differs depending on the brand you own.