I would suggest a search on youtube for Derek Prince. He has many videos which teach how to cast demons out.
His teachings say, Jesus didnt pray to cast demons out, Oh Lord, cast these demons out of this man! Jesus didnt do that. Jesus walked in authority and commanded them to leave Himself.
Jesus also gave us this authority in His name.
Matthew 10:
1 And when he had called unto him his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease.
2 Now the names of the twelve apostles are these; The first, Simon, who is called Peter, and Andrew his brother; James the son of Zebedee, and John his brother;
3 Philip, and Bartholomew; Thomas, and Matthew the publican; James the son of Alphaeus, and Lebbaeus, whose surname was Thaddaeus;
4 Simon the Canaanite, and Judas Iscariot, who also betrayed him.
5 These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not:
6 But go rather to the lost sheep of the house of Israel.
7 And as ye go, preach, saying, The kingdom of heaven is at hand.
8 Heal the sick, cleanse the lepers, raise the dead, cast out devils: freely ye have received, freely give..../KJV
If anyone tells you that Jesus gave this authority to only the Apostles, don't listen to them. God is no respecter of persons and those words are for you & I too.