Remove the covers from the roller adjustment screws and turn the screw counterclockwise to lower the door.
Lift the door up and out of the track. Do the same with the other door.
Remove the bottom track from the door frame by removing the screws. Reverse its direction and screw it back down.
Insert the top of the door into the top track, door reversed, and set the roller into the lower track. Do this with the second door as well. Raise the rollers by screwing clockwise until the door is raised.