You can perform a half halt with any type of rein. The purpose of a half halt is to attract the horse's attention, to make it change gait, to slow it down and/or to make it push its hind legs further under the body. To do this, first sit very straight in the saddle. You should imagine that you are reaching the sky with your head and to the ground with your feet. By stretching your body in this way, you give your horse weight support on both sides. Then, increase the pressure of your legs around the horse's belly. These two aids cause your horse to push his legs further under his body. This gives the horse the impulse to move forward. Now you should counteract with the reins just enough so that your horse goes at a slower pace or changes gait.