My understanding—and the clerk can comment and say whether I'm correct or not—is that I as the chair would need four members of this committee to indicate to me in writing that they would want to have a meeting.
I've never had a meeting by conference call, but my understanding is that to call a special meeting to discuss this prior to our Tuesday meeting, we would need four members of the committee to sign a letter stating to me why they wished to do so.
Michelle will comment on the procedure.