Gentle Singer: There is no need to panic. The person who will be pitching the selections during the day is designated in advance by the chairman of the convention. After your song selection is announced, nod to that person and say softly "key please." (All convened should remain silent with no talking or humming, as supplying the appropriate notes is no easy task).
     You may ask anyone else to pitch your selection if you prefer. All that is necessary is to softly yet clearly announce to the designated keyer that you have asked Ms. So-and-so to pitch this song. Of course, you will have asked Ms. So-and-so beforehand so that she will be ready to give the key promptly.

     As the opening pitches are given out, raise your hand, and, as you hear the class around you getting their notes, commence.