Today, November 2, when the Church celebrates the Commemoration of the Faithful Departed, a plenary indulgence can be obtained for the soul of a loved one, family member or friend.
Just as the saints intercede with God for us, we can pray to the Lord for the souls in Purgatory.
"All the baptized on earth, the souls in Purgatory and all the blessed who are already in Paradise form one great Family. This communion between earth and heaven is realized above all in intercessory prayer."
According to the Indulgentiarum Doctrina (Norm 15), a Catholic can gain plenary indulgence for a deceased person "in all churches, public or - by those who legitimately employ them - semi-public oratories" and following the usual conditions for gaining a plenary indulgence.
The usual conditions for gaining a plenary indulgence are sacramental confession, renunciation of all sin, Eucharistic communion and prayer for the Pope's intentions.
What is a plenary indulgence?
"By plenary indulgence is meant the remission of all temporal punishment merited for sin, so that no further expiation is necessary in Purgatory."
"In the Sacrament of Penance the guilt of sin is removed and, together with it, also the eternal punishment merited by sin; but the temporal punishment required by divine justice remains, and this requirement must be satisfied either in this life or in the life to come, that is, in Purgatory."
In other words, plenary indulgence "restores" the soul to the state it was in when it received Baptism. If a person dies after receiving this gift, he or she goes directly to Heaven.