From the Catechism of the Catholic Church, No. 1022:
"Each man receives his eternal retribution in his immortal soul at the very moment of his death, in a particular judgment that refers his life to Christ: either entrance into the blessedness of heaven – through a purification or immediately or immediate and everlasting damnation."
Rooted in ancient Christian tradition, St. Odilo of Cluny established a memorial of all the faithful departed in the year 988. It was accepted in Rome in the 13th century. The official name of the celebration in the Roman Catholic Church is "The Commemoration of All the Faithful Departed."
At death, we are the sum of who we are ... good and evil. Our soul departs from the body and we stand before the Judgment Seat of our Lord, Jesus Christ, to give an account of our lives. Christianity rejects reincarnation. We live only one life and then die once. We are a Communion of Saints, and here on earth, we pray for one another and the souls being purified in Purgatory. The Saints in Heaven intercede for us on our earthly pilgrimage, that we might live and die in God's grace and join them in Heaven.
For our beloved dead, we pray:
Eternal rest grant unto them, O Lord, and let perpetual light shine upon them. May they rest in peace. May their souls and the souls of all the faithful departed, through the mercy of God, rest in peace. Amen.