Under NASPA tournament rules, a player may request to "hold" the opponent's play in order to consider whether to challenge it, provided that the opponent has not yet drawn replacement tiles. If player A holds, player A's clock still runs, and player B may not draw provisional replacement tiles until 15 seconds after the hold was announced (which tiles must then be kept separate). There is no limit on how long player A may hold the play. If player A successfully challenges after player B drew provisional replacement tiles, player B must show the drawn tiles before returning them to the bag.