You might, it is fairly commonplace, set out to change, to become another, to will a different self into existence. Imagine then, that you succeed.
There is a break in your experience. What being now looks through your eyes? A creature made not born, a new tenant in the old body.
And what has become of that which was? Those traits, habits and foibles which had become so familiar? Your memories are no longer your own. They belong to another. To the self you have murdered.
What have you become?
Who ARE you?