The Ceremony of Release is celebrated for the elderly at the House of the Old.
Jonas goes to the House of the Old because Asher and Fiona are there. He is spending his last volunteer hours before the Ceremony of Twelve with his friends. The House of the Old is “a serene and slow-paced place” (ch 4, pp. 28-29). Larissa, the old woman Jonas helps bathe, tells him about the Ceremony of Release celebrated for a man named Roberto.
"Well, there was the telling of his life. That is always first. Then the toast. We all raised our glasses and cheered. We chanted the anthem. He made a lovely good-bye speech. And several of us made little speeches wishing him well. (ch 4, p. 32)
Larissa explains that she is not sure what happens during the actual release. He just goes through a door, and is never seen again. Jonas does not find out until later that release means death by lethal injection. When he finds out what release actually means, he is very upset. That is when he decides to leave the community.
Lowry, Lois (1993-04-26). The Giver (Newbery Medal Book). Houghton Mifflin Harcourt. Kindle Edition.