If no deacon is present, after the Prayer of the Faithful is concluded and while the priest remains at the chair, the acolyte places the corporal, the purificator, the chalice, the pall, and the Missal on the altar. Then, if necessary, the acolyte assists the priest in receiving the gifts of the people and, if appropriate, brings the bread and wine to the altar and hands them to the priest. If incense is used, the acolyte presents the thurible to the priest and assists him while he incenses the gifts, the cross, and the altar. Then the acolyte incenses the priest and the people.
A duly instituted acolyte, as an extraordinary minister, may, if necessary, assist the priest in giving Communion to the people.100Paul VI, Apostolic Letter Ministeria quaedam, 15 August 1972: AAS 64 (1972), p. 532. If Communion is given under both kinds, when no deacon is present, the acolyte administers the chalice to the communicants or holds the chalice if Communion is given by intinction.
Likewise, when the distribution of Communion is completed, a duly instituted acolyte helps the priest or deacon to purify and arrange the sacred vessels. When no deacon is present, a duly instituted acolyte carries the sacred vessels to the credence table and there purifies, wipes, and arranges them in the usual way.
After the celebration of Mass, the acolyte and other ministers return in procession to the sacristy, together with the deacon and the priest in the same way and order in which they entered.