Some thoughts here:
1.) An extraordinary minister of Holy Communion is not a person, it is not a title, it is not an office. It is a duty that can be performed by a lay person at Mass should there be, in the judgement of the celebrant, an insufficient number of ordained ministers to distribute.
…
From the Catechism of the Catholic Church:
“1672 Certain blessings have a lasting importance because they consecrate persons to God, or reserve objects and places for liturgical use. Among those blessings which are intended for persons - not to be confused with sacramental ordination - are the blessing of the abbot or abbess of a monastery, the consecration of virgins, the rite of religious profession and the blessing of certain ministries of the Church (readers, acolytes, catechists, etc.). the dedication or blessing of a church or an altar, the blessing of holy oils, vessels, and vestments, bells, etc., can be mentioned as examples of blessings that concern objects.”
Paul VI began his1972 Motu Proprio Ministeria Quaedam:
"Certain ministries were established by the Church even in the most ancient times for the purpose of suitably giving worship to God and for offering service to the people of God according to their needs. By these ministries, the offices to be carried out in the liturgy and the practice of charity, deemed suitable to varying circumstances, were entrusted to the faithful. The conferring of these functions often took place by a special rite, in which, after God’s blessing had been implored, a Christian was established in a special class or rank for the fulfillment of some ecclesiastical function.
Some of these functions, which were more closely connected with the liturgical celebration, slowly came to be considered as a training in preparation for the reception of sacred orders. As a result, the offices of porter, reader, exorcist, and acolyte were called minor orders in the Latin Church in relation to the subdiaconate, diaconate, and priesthood, which were called major orders. Generally, though not every where, these minor orders were reserved to those who received them as steps toward the priesthood.
Nevertheless, since the minor orders have not always been the same and many functions connected with them, as at present, have also been exercised by the laity, it seems fitting to reexamine this practice and to adapt it to contemporary needs."
A person becomes an Extraordinary Minister of Holy Communion with varying degrees of permanence. It can be for one occasion. It can be for a set period of time. It the case of an instituted acolyte there is not time limit. Each method has a different liturgical ceremony associated with it.