[151.] Only out of true necessity is there to be recourse to the assistance of extraordinary ministers in the celebration of the Liturgy. Such recourse is not intended for the sake of a fuller participation of the laity but rather, by its very nature, is supplementary and provisional. Furthermore, when recourse is had out of necessity to the functions of extraordinary ministers, special urgent prayers of intercession should be multiplied that the Lord may soon send a Priest for the service of the community and raise up an abundance of vocations to sacred Orders.
[158.] Indeed, the extraordinary minister of Holy Communion may administer Communion only when the Priest and Deacon are lacking, when the Priest is prevented by weakness or advanced age or some other genuine reason, or when the number of faithful coming to Communion is so great that the very celebration of Mass would be unduly prolonged. This, however, is to be understood in such a way that a brief prolongation, considering the circumstances and culture of the place, is not at all a sufficient reason.