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.
Vince Lampert
The Reverend Vincent Lampert, MDiv, is an American Roman Catholic Priest and the designated exorcist of the Roman Catholic Archdiocese of Indianapolis. Father Lampert was appointed to become an exorcist by Archbishop Daniel M. Buechlien. He is one of the few exorcists known to use social media like Twitter ( @FrVinceLampert ) on a regular basis. In one article he told the reporter that he is fighting the devil by tweeting about exorcism.