Is it possible to change direction of DC motor using a 3-state rocker switch?
You can do what you want if you have two batteries. 

Connect both batteries in series. Connect both outside terminals of the switch to the outside ends of the batteries. 

Finally, connect the motor between the center terminal of the switch and the midpoint of the two batteries.

One battery runs the motor in one direction, the other battery powers the motor in the opposite direction.