No human being can exorcise a demon possessed person by him or herself. A demon can only be exorcised from a possessed person by the agency of God’s angels. The priest, imam, rabbi or shaman must always invoke God and his Angels to fight the demon. All evil spirits feed off of human narcissism, and if an exorcist begins to believe that he (or she) holds the power to banish it, the demon always wins.
Be wary of anyone claiming to be an exorcist who is not directly connected with an established church or an established Native American shaman. Under no circumstances should anyone claiming to be an exorcist charge you money to free you from a demon!!! Many people have been bankrupted by con artists pretending to be exorcists. Exorcists are VERY special people. Each and every officially sanctioned Catholic or mainstream Protestant exorcist has undergone years of vetting by their church hierarchy. They must be absolutely pious in order to confront these vile entities. They must be entirely knowledgeable about the spiritual and demonic worlds. They must possess an unshakable inner strength and be completely in command in situations of wild pandemonium.
Just being a charismatic person who believes in God does not qualify anyone to be an exorcist. Simple knowledge of scripture is insufficient. The demon can quote scripture verbatim. Presumably, they have all existed since the beginning of time, and each one has probably possessed thousands of people. They aren’t all especially intelligent, but each and every one has an unlimited knowledge of human history. An untrained exorcist or even an untrained self-proclaimed fundamentalist pastor may be able to rid a possessed parishioner of a human spirit, but if he (or she) tries the same tactics on a real demonic entity, the exorcist is likely to suffer possession him/herself. There really is a difference between an evil human spirit and a demonic entity, and if the “exorcist” can’t tell the difference immediately, things can go very badly