What does this quote mean when you let go of what you are you become what you might be?

When you define yourself as something, you limit yourself to that something. When you let go of that definition, it opens up the whole world of possiblilities and makes it possible for you to become something more. For example, for many years I have defined myself as a CPA and that limited me to the accounting world. I have finally let go of that definition and I realize I am free to be whatever I want -- which is really Human Resources Manager. But I will not define myself as Human Resources Manager because that would limit my potential -- who knows what I might become if I keep my possibilities open.