Regression means to go back to former lives or the start of this life.
There are several ways of doing regression therapy, including hypnosis.
My advice, when considering hypnosis, is to never go alone and make sure the other person tapes the session. If a Regression therapist refuses these requests then it's better to look for another therapist.

My way of doing Regression is by writing 3 questions about recurring problems in your life.
First, the client lies on a treatment table to do some breathing exercises in order to gain total relaxation, somewhere between sleep and wakefulness. My Guides and the client's Guides will work together to lead us by visions, feelings, emotions and words to the places and circumstances in another life in order to help solve the problems of this life. I write down every question, answer and situation, After the session, I summarize it all with explanations and mail it within 3 weeks to your home address.