The software allows you to immediately rebuy a player when you bust him or her out of the tournament for that very reason: to allow the player to stay in the same seat. If you do not want the player to stay in the same seat, just do not rebuy the player during the bust-out process. After the player has been busted out, then rebuy the player and, if automatic balancing is enabled, the software will attempt to seat the player (likely somewhere else, but it could be the same spot).