Exorcism
In Catholic Christianity, exorcisms are performed in the name of Jesus Christ. A distinction is made between a formal exorcism, which can only be conducted by a priest during a baptism or with the permission of a bishop, and "prayers of deliverance" which can be said by anyone.
The Catholic rite for a formal exorcism, called a "Major Exorcism", is given in Section 11 of the Rituale Romanum. The Ritual lists guidelines for conducting an exorcism, and for determining when a formal exorcism is required. Priests are instructed to carefully determine that the nature of the affliction is not actually a psychological or physical illness before proceeding.
Exorcist II: The Heretic
Philip Lamont, a priest struggling with his faith, attempts to exorcise a possessed South American girl who claims to "heal the sick". However, the exorcism goes wrong and a lit candle sets fire to the girl's dress, killing her. Afterwards, Lamont is assigned by the Cardinal to investigate the death of Father Lankester Merrin, who had been killed four years earlier in the course of exorcising the Assyrian demon Pazuzu from Regan MacNeil. The Cardinal informs Lamont (who has had some experience at exorcism and has been exposed to Merrin's teachings) that Merrin is facing posthumous heresy charges because of his controversial writings as Church authorities are trying to modernize and do not want to acknowledge that Satan exists.