During a sermon one day, the holy Curé of Ars gave the example of a priest who, celebrating Mass for a deceased friend, after the Consecration prayed as follows, "Holy and Eternal Father, let us make an exchange. You possess the soul of my friend in Purgatory; I have the Body of Your Son in my hands. You liberate my friend for me, and I offer to You Your Son, with all the merits of His Passion and Death."
~ From Jesus Our Eucharistic Love by Fr. Stefano Manelli, O.F.M. Conv., S.T.D.~