"In every celebration of the Eucharist, there should be a sufficient number of ministers of Holy Communion so that it may be distributed in a reverent and orderly manner. Bishops, priests and deacons distribute Holy Communion in virtue of their office as ordinary ministers of the Body and Blood of the Lord. 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).'"
Extraordinary Ministers of Holy Communion should receive sufficient spiritual, theological, and practical preparation to fulfill their role with knowledge and reverence. All ministers of Holy Communion should show the greatest reverence for the Most Holy Eucharist by their demeanor, their attire, and the manner in which they handle the consecrated bread or the consecrated wine" (http://www.usccb.org).
Nominations of qualified parishioners are accepted by the pastor.