Catholics might pray thus when casting out Satan ...
Almighty Lord, Word of God the Father, Jesus Christ, God and Lord of all creation; who gave to your holy apostles the power to tramp underfoot serpents and scorpions; who along with the other mandates to work miracles was pleased to grant them the authority to say: "Depart, you devils!" and by whose might Satan was made to fall from heaven like lightning; I humbly call on your holy name in fear and trembling, asking that you grant me, your unworthy servant, pardon for all my sins, steadfast faith, and the power - supported by your mighty arm - to confront with confidence and resolution this cruel demon. I ask this through you, Jesus Christ, our Lord and God, who are coming to judge both the living and the dead and the world by fire.
And ...
I cast you out, unclean spirit, along with every Satanic power of the enemy, every spectre from hell, and all your fell companions; in the name of our Lord Jesus +Christ. Be gone and stay far from this creature of God.+ For it is He who commands you, He who flung you headlong from the heights of heaven into the depths of hell. It is He who commands you, He who once stilled the sea and the wind and the storm. Hearken, therefore, and tremble in fear, Satan, you enemy of the faith, you foe of the human race, you begetter of death, you robber of life, you corrupter of justice, you root of all evil and vice; seducer of men, betrayer of the nations, instigator of envy, font of avarice, fomenter of discord, author of pain and sorrow. Why, then, do you stand and resist, knowing as you must that Christ the Lord brings your plans to nothing? Fear Him, who in Isaac was offered in sacrifice, in Joseph sold into bondage, slain as the paschal lamb, crucified as man, yet triumphed over the powers of hell. (The three signs of the cross which follow are traced on the brow of the possessed person). Be gone, then, in the name of the Father, + and of the Son, + and of the Holy + Spirit. Give place to the Holy Spirit by this sign of the holy + cross of our Lord Jesus Christ, who lives and reigns with the Father and the Holy Spirit, God, forever and ever.