One of the most valuable uses of the hypnotic trance is clearing the negative impressions that we all tend to carry around and which impact our lives in complex and often very adverse ways.  These are often so deep in our sub-conscious that we really have no idea they are there.  Or, if we are aware of them , we may discount their significance.  Quite often, aspects of our personality that we are secretly unhappy with will be symptoms of these hidden impressions.  What to do? 
The first step is to admit to oneself that maybe, just possibly, there is something going on at a subliminal level that just might be affecting our every day behavior in a negative manner.  This is often very hard to think about but once you do, you are on the right path to discovery and then transformation of a negative impression into something positive.   
An impression is really the manner in which we experienced an event, often a traumatic event.   What the hypnotist does is to first identify the event, if it is not known, by using what we call regression therapy, then the hypnotist and the client work together to re-script the impression.  All this can take several sessions but the outcome is a cleansing of the psyche and a genuine shift in self awareness leading to enhanced self-confidence.