To dream that you or others are being exorcised symbolises your initiative to regain control and take steps toward the direction of your goals. Alternatively, you may not be taking responsibility for your actions and are looking for a scapegoat.
Dreaming of performing exorcism on someone indicates that you are stepping up and taking control of a situation. Alternatively, to dream that you are exorcising someone implies that you want control of something that this person has. Consider what this person has that you also want in your life.