People who undergo hypnosis (to hypnotize) are actually de-hypnotizing themselves. This is because we have been conditioned for various habits and behaviours since young.
For instance, some people hypnotize themselves to stay quiet in a social setting because they ‘learned’ it since young that it is not polite or appropriate to talk much. As a result of such conditioning, it landed them an introvert and quiet person.
When they go to a hypnotherapist to get their anti-social behaviour cured, they are de-hypnotizing from their anti-social habits.