Well people do in fact change their fundamental values and morals sometimes, and this process is sometimes trained by others.

I'm thinking of two extreme cases in opposite directions: addiction recovery groups, and the process of training someone to be a torturer.

People who successfully recover from addiction to alcohol or drugs or sex often go through a process of examining their morals and changing fundamental aspects of their belief system and morality, from thinking that doing drugs and alcohol are good and positive things, to thinking they are very negative and harmful things. This is obviously a positive change for the better which usually happens slowly over time, but clearly for some people is a rapid event. Many people who make this change will say they simply clarified, not changed their values, but if values are represented by actions and even verbal opinions, clearly their values have changed significantly.

In the opposite case, I have heard that how torturers are trained is that first an existing torturer selects someone who has some personality traits that seem to indicate some latent sociopathy. Then they progress in stages: having the new recruit stand outside the room and listen, then sit in the same room while the torture is taking place (by someone else), then participate in little ways, then fully participate, and so on. You could again say that this person was always inclined this way which is why they were selected, but it was merely a latent potentiality. The same person could be a surgeon and save lives instead of taking them with the skills they have of dissociating from the other person's pain. No one is born a torturer, they must be molded or trained, with certain extremely harmful behaviors rewarded.

In both of these cases "trance" or "hypnosis" is apparently not used, but as we know, trance is a natural phenomenon that is simply amplified by the hypnotist. I have no doubt that people who recover from addictions enter trance states where they experience changes, and that people who become torturers enter trance states when in the room with someone being tortured.

With the right context and enough time, I believe many people can be lead to do things opposite to what they used to believe was their fundamental values and morals, but they will likely justify these actions as having always been consistent with their fundamental morality. If they can't justify their actions, they will feel incredibly high levels of guilt. Within a single hypnosis session it is unlikely that an individual practitioner can get someone to do something opposite to their values, but over time I have no doubt that such changes can occur, which is why psychotherapy is a regulated industry in virtually all developed nations, because even without formal trance, power dynamics can lead to undue influence which can cause harm.