As an Apostolic missionary to Europe and Africa and eventually Asia I only approach a person who has a demon or more if the Holy Spirit leads me to do so and as I do approach that person I'm very careful in what I do or don't do making sure I'm getting my directions from the Holy Spirit, and that works all the time as long as I'm full of faith and not doubting or wavering, because he's the one who drives them out and not me, Spirit to spirit