This is a very important question. It won't need a long explanation. This should be a statement shouted from the rooftops. The energy, time and commitment to try to change somebody is not worth it. Basically the person will only change if they want to.
It is not your responsibility to change or fix them. Let them be who they are, and you be yourself. I think you already knew the answer when you wrote the question. Maybe not, what is important is that you know not to try to fix others, or let them try to fix you. You will have a much happier and saner life.