In the relatively short history of modern hypnotism, there have been dozens of hypnotic techniques and a wide range of explanations of the phenomenon. The only constant through all of this has been the hypnotic subjects themselves. No matter how you view the art of the hypnotist, it is undeniable that people do enter a special state in which they are abnormally suggestible and uninhibited.
Modern skeptics have a sound and convincing explanation of this unusual state. Hypnotic subjects aren't actually in a trance state, they argue, they only think they are. Social pressure and the influence of the hypnotist are often enough to convince people that they should act a certain way. When they find themselves heeding the suggestions, they think they must be in a hypnotic trance. Proponents of this theory contend that this belief alone may be powerful enough to bring about remarkable changes in a person. If you think someone is compelling you to act a certain way, you will act that way. If you think hypnotic suggestion will ease your pain, your mind will bring about this feeling.
In this view, an effective hypnotist isn't one that can probe the hidden reaches of your mind, but one with strong enough authority and charisma to convince you to go along.
In the general sense, this phenomenon is known as the placebo effect. In numerous studies, people who were given ordinary sugar pills behaved and felt differently only because they thought they should. It's clear that the mind can influence all aspects of the physical body, so it makes sense that a firmly held belief can reduce pain or even help treat a disease.
But in the end, this explanation of hypnosis amounts to pretty much the same thing as the trance theory. When you absolutely convince somebody that you've brought about a change in their subconscious, they register this information as a fact. Like any fact, this information will take root in the subconscious mind. So, even if the hypnotic state is nothing more than a figment of the subject's imagination, hypnotic suggestions can still reform their deeply held beliefs. The end result is the same!
To find out more about hypnosis, and to explore the various uses of hypnotism, check out the links below.