Col. Carde helps this rider establish a more giving hand. He gets on the mare and rides her and you can see the difference with a more giving hand. They play with the piaffe and passage.
Col. Carde shows the proper rein hold and angle to strive for in addition to beginning the piaffe and passage. In this piece, the mare is resistant to the contact and there is discussion and instruction to specifically work on lessening the resistance.