The Laws allow any player to try to prevent another player from committing an infraction or irregularity. Once an irregularity has occurred, it can no longer be prevented from happening. A common example is dummy stating that declarer has led from the wrong hand. Before declarer leads from the wrong hand, dummy may try to prevent him from doing so; once declarer has done so, this irregularity can no longer be prevented. Dummy cannot be the first to point out an irregularity or to summon the Director before attention has been legally drawn to the irregularity by another player.