Go 4 on 4 halfcourt. When coach yells "switch" or "change", the attackers put the ball on the floor and switch to defence, but must first touch the lane with one foot, and can't guard the player who was guarding them. The former defenders can get the ball and attack immediately.
Dick Bennett - use to practice converting from offence to defence, along with 3 on 2 to 2 on 1.
See Scrimmage - Whistle, Defending - Woodley 4 on 4 (change),