I never saw anyone professionally, but let me add my experience just for expanded perspective on this.
I attended a small town “whatever” days celebration. There was a hypnotist there, for fun. He spoke of his credentials, and some practical uses for what he does. He then took about ten volunteers. I was one.
We lined up on a flatbed truck in front of a row of folding chairs.
He went to each one before starting and asked if we wanted him to give us a useful post hypnotic suggestion at the end. I chose smoking.
It was fun.
I felt light, like I weighed about twenty pounds.
I could hear the guy’s voice, far away, but clear. Of course, he was using a mic, but I was somewhere else.
He got us to do stuff. Family show, so it was within reason. It was all in fun, and I didn’t resist a thing.
Found out later even the sweet little old lady fipped off the imaginary traffic cop.
When he did my post hs, he specified I would remember everything. He said I would smoke as normal, but only three cigarettes. The fourth cigarette would taste like crap, and I would not want it.
Well, it went just like that. I took one puff of the fourth cigarette, it was nasty. I tossed it, and lit the fifth.
I think the guy could have stopped my smoking, if I paid him, and he wanted to. I would also have to want to cooperate.
I saw a way around the loophole he left me, and took it.