I once knew someone who was deeply troubled and vulnerable (read: complete and utter train wreck).
One night, something took over her body. She was not herself. She dropped like a marionette with its strings cut (cliché, I know), only in slow motion. And she began to twitch (she wasn’t having a seizure).
While everyone else watched in horror (and most of the people in that room were experienced occultists or witches), I used every ounce of my energy to mentally force the entity (or whatever it was) out of her body. Another friend pushed the presence out of the nearby window, then sealed it with a pentagram.
The victim woke up, with no idea what had happened. She was still a total mess, but to my knowledge the entity never bothered her again.