Can a person change their personality?

I think the question really should be, Why would you want to? Well I think certain situations in life determine how you should respond. If your not use to being those situations then you won’t do a good job at it, whatever it is. Which means you’ll feel uncomfortable then lowering your self esteem. Learning how to “be” in any and all is the trick, this can give you a connection in life which in turn will help you to relax. So I ask you is this changing your personality or just a life lesson?