One way to help us realize “I am not this body” is to remember that forgetfulness generally happens when we change bodies. Actually the body is constantly changing, so we’re constantly forgetting. But the reason we can’t remember past lives is because we have completely changed bodies.
A great way to explain this is as follows. When I dream vividly, I think it’s real. Therefore I am totally forgetting that I’m the body lying in the bed.
Near death experiences and other out of body experiences are also convincing (sometimes clinically proven) evidence of the soul being distinct from the body.
The subtle body of mind, intelligence and ego is at work during dreams.