[bigwhistle]

When I pregame this situation, this is the tact that I take with the crew that I am working with that night.

If you feel that the call needs to be changed, DO NOT BLOW YOUR WHISTLE! Come toward me with a raised hand (indicating do not start clock). If I made the call for a specific reason (i.e. the ball was off of A1 but B1 probably made enough contact for a foul to be called but I passed on it, opting to just give the ball OOB to the team that deserved it), I will give the partner the Stop Sign.

If I allow him to come to me with info, as JRut properly desribed it above, I will always change the call, since he would not have come to me if he was not 120% sure that I did not see what happened. Many times this will involve a pass that was tipped just after leaving the hand of the passer in my partner's primary which I did not see.

The reason that the partner should not blow his whistle is that the whistle will now draw the attention of everyone in the gym to him. Once this happens, the call needs to be changed, or the credibility of the crew starts to deteriorate in the minds of many. Before the ball is ever put in play, we should always find our partners to make sure they are ready. Because of this, his approaching with a raised arm tells me something that I did not know about happened.

As BBRef stated, the official making the initial call should be the one to change the call if it is to be changed.