Exorcism
In Christianity, exorcism is the practice of casting out demons. In Christian practice the person performing the exorcism, known as an exorcist, is often a member of the Christian Church, or an individual thought to be graced with special powers or skills. The exorcist may use prayers and religious material, such as set formulas, gestures, symbols, icons, amulets, etc. The exorcist often invokes God, Jesus and/or several different angels and archangels to intervene with the exorcism. Protestant Christian exorcists most commonly believe the authority given to them by the Father, Son, and Holy Spirit (the Trinity) is the source of their ability to cast out demons.
Exorcism in the Catholic Church
In the process of an exorcism the person possessed may be restrained so that they do not harm themselves or any person present. The exorcist then prays and commands for the demons to retreat. The Catholic Priest recites certain prayers the Our Father, Hail Mary, and the Athanasian Creed. Exorcists follow procedures listed in the ritual of the exorcism revised by the Vatican in 1999. Seasoned exorcists use the Rituale Romanum as a starting point, not always following the prescribed formula exactly. "The Gale Encyclopedia of the Unusual and Unexplained" describes that an exorcism was a confrontation and not simply a prayer and once it has begun it has to finish no matter how long it takes. If the exorcist stops the rite, then the demon will pursue him which is why the process being finished is so essential. After the exorcism has been finished the person possessed feels a “kind of release of guilt and feels reborn and freed of sin.” Not all exorcisms are successful the first time; it could take days, weeks, or months of constant prayer and exorcisms.