How we change what others think, feel, believe and do
After you have completed your main conversation with the other person, make one more final request. The request may be for information or it may be for agreement to act in some way.
Request language may be something like:
The main conversation may be significant or it may be inconsequential. Importantly, it should set up the situation to support the final request, where significant benefit is gained.
The request may well be made as you are actually walking away or even half-way out of the door. As you pause, it helps if the other person has to take a few steps towards you.
A sales person knocks on a person's door to let them know that they have left their car lights on. They are thanked and are just leaving, when they turn around and say 'Oh one more thing. I'm doing a survey of needs in the area. Could I pop back tomorrow to discuss?'
A person is going to work after a breakfast conversation. As they go out of the door, they call 'I may be late -- could you pick up the kids?'
A detective has been questioning a suspect. She closes the interview and are walking away when she turns and says 'Michael was there, wasn't he?'
After the main conversation, the other person will relax as they reach closure about this interaction. As such, they may well be open and unprepared for the final request, and so agree to it without much thought.
If the main conversation was one in which the person became tense, for example where you were questioning them closely, they will be particularly relaxed, especially if they think they have got away with something. This makes them particularly vulnerable to the casual question of a final request.
Getting the other person to walk towards you as you leave causes them to make an effort, albeit small. They have to explain this to themself and typically do so by believing they want to help you. Consequently, they are more likely to give you what you seek.
Another effect of the final request is that, as you are on your way out, there is little space for objection or re-opening of discussions. This hurries the other person into a response.
In the TV detective series 'Columbo', starring Peter Falk, the 'Columbo Technique' often included the use of 'one more thing' at the end.