When the size of the congregation or the incapacity of the bishop, priest, or deacon requires it, the celebrant may be assisted by other bishops, priests, or deacons. If such ordinary ministers of Holy Communion are not present, "the priest may call upon extraordinary ministers to assist him, i.e., duly instituted acolytes or even other faithful who have been deputed for this purpose. In case of necessity, the priest may also depute suitable faithful for this single occasion (GIRM 162)."