Do your best to draw the person out of any drug-using environment they might be immersed in. Try to schedule the intervention for a time when they are the most likely to be sober or mostly sober. Bring the individual to a place where you will not be interrupted. Remove any children (and pets) from the area. If the person is driving work out a way that their car may be blocked in after they arrive, disabled or whatever. If they blow up and leave make sure it is on foot only if possible.