On a Clear Day You Can See Forever (1970)

Daisy Gamble, an unusual woman who hears phones before they ring, and does wonders with her flowers, wants to quit smoking to please her fiancé, Warren. She goes to a doctor of hypnosis to do it. But once she's under, her doctor finds out that she can regress into past lives and different personalities, and he finds himself falling in love with one of them.