A system is disclosed for converting an overhead door into a gate or serving window, the system having at least two rows of panels spanning the width of the door, one panel located above and adjacent to the other panel, a pair of rails opposite one another and adjacent to the panels, the panels traveling within the rails to move from a closed position to an open position, and at least one hinge connecting the lower row of panels to the upper row of panels, the hinge having an upper half attached to the upper row of panels and a lower half attached to the lower row of panels, the upper and lower halves of the hinge connected by a removable central pin, wherein the upper row of panels moves from the closed position to the open position when the central pin is removed from the hinge.