I have heard of “step-ins” before, only the term I heard used was “walk-in.” A walk-in is typically considered to be a more evolved soul that takes over an adult body to complete tasks on the planet. This often happens after a traumatic event in which the old soul is unable to maintain the life force to keep the body alive. Many have speculated that self-help guru Byron Katie is a walk-in, because of her miraculous transformation during a period of deep depression and complete split with her previous personality.