§1. A pastor ceases from office by removal or transfer carried out by the diocesan bishop according to the norm of law, by resignation made by the pastor himself for a just cause and accepted by the same bishop for validity, and by lapse of time if he had been appointed for a definite period according to the prescripts of particular law mentioned in can. 522.
§2. A pastor who is a member of a religious institute or is incardinated in a society of apostolic life is removed according to the norm of can. 682, §2.
§3. When a pastor has completed seventy-Five years of age, he is requested to submit his resignation from office to the diocesan bishop who is to decide to accept or defer it after he has considered all the circumstances of the person and place. Attentive to the norms established by the conference of bishops, the diocesan bishop must provide suitable support and housing for a retired pastor.
Source: Code of Canon Law (Vatican.va)