"Can personality change?", is a question that has absorbed psychologists since William James first proposed that personality was "set in plaster" by early adulthood. While there is substantial evidence for both personality stability and change, the trick is to understand what changes and what does not, when to expect stability and when to expect change, and why these occur as they do.
Miller, W. R., & C'deBaca, J. (1994). Quantum change: Toward a psychology of transformation. In T. Heatherton & J. Weinberger (Eds.), Can personality change? (pp. 253-280). Washington, DC: American Psychological Association