Q: As a bishop, I do not often celebrate weddings, but I will be presiding for one soon. A priest will concelebrate. May I delegate him to give the nuptial blessing?
A: The Ceremonial of Bishops envisions two options: The bishop celebrates the Mass, and a priest concelebrates. Or the priest celebrates the Mass, and the bishop presides wearing a cope (601).
In the first instance, the only action assigned to the priest is the greeting of the couple at the beginning of the service (602). If the couple are processing together from the door, the priest greets them at the door. If the couple do not join arms until they enter the sanctuary, then the priest greets them in the sanctuary. As I understand the history of this greeting, its nature is to help the couple make the transition from the secular world outside the church to the sacred space within. This informal greeting should be friendly, warm and welcoming. The bishop celebrates the Mass, receives the consent of the couple, and imparts the nuptial blessing (607-608, 611).
If the priest celebrates the Mass while the bishop presides, the bishop gives the homily (606) and receives the consent of the couple (607-608), but the priest who celebrates the Mass imparts the nuptial blessing (611). Near the end of the Mass, the bishop imparts the final blessing.