One and the same priest celebrant must always exercise the presidential office in all of its parts, except for those parts which are proper to a Mass at which the Bishop is present (cf. no. 92).
If there are several persons present who are able to exercise the same ministry, nothing forbids their distributing among themselves and performing different parts of the same ministry or duty. For example, one deacon may be assigned to take the sung parts, another to serve at the altar; if there are several readings, it is well to distribute them among a number of lectors. The same applies for the other ministries. But it is not at all appropriate that several persons divide a single element of the celebration among themselves, e.g., that the same reading be proclaimed by two lectors, one after the other, except as far as the Passion of the Lord is concerned.
If only one minister is present at a Mass with a congregation, that minister may exercise several different duties.
Among all who are involved with regard to the rites, pastoral aspects, and music there should be harmony and diligence in the effective preparation of each liturgical celebration in accord with the Missal and other liturgical books. This should take place under the direction of the rector of the church and after the consultation with the faithful about things that directly pertain to them. The priest who presides at the celebration, however, always retains the right of arranging those things that are his own responsibility.90Cf. Second Vatican Ecumenical Council, Constitution on the Liturgy, Sacrosanctum Concilium, no. 22.