Just to clarify, normally in the event that the chair cannot act as chair, the vice-chair assumes the chair; or in the event that the vice-chair is not available, the second vice-chair assumes the chair. But in the event that neither one of those two vice-chairs is able to fill the role of chair, this motion empowers the chair to designate another member of the committee to sit in for the chair.
On February 5th, 2009. See this statement in context.