Once a priest, always a priest: the Sacrament of Holy Orders imprints an indelible character on the soul of the priest that empowers him to confect the sacraments. However, if a priest has been laicized, which is to say, returned to the lay state, he may no longer dress as a priest or function as a priest. He is not allowed to celebrate the sacraments, but he would be allowed to receive the sacraments.
If he were to come across a person in danger of death, he would still have the power to forgive sins through sacramental absolution, and in such a case he would be allowed to do so.
Laicization can be either voluntary as a favor, or involuntary as a punishment. In either case, the man is no longer allowed to carry out the sacramental duties of an ordained cleric with that one exception: in danger of death he can hear a person’s confession (see Canons 976, 986.2, 1335).
Finally, it is possible for a laicized priest to be restored to holy orders, but only by express rescript from the pope (see Canon 293).
Rev. Francis Hoffman, J.C.D., Executive Director of Relevant Radio. Follow him on his Facebook page “Father Rocky.”