Selfish person

Do you think therapy can help someone become unselfish? I’ve seen there is therapy for narcissism. It’s not that extreme, but it could one day turn into that. I’m not going to try to change someone because I know the consequences of that so I don’t need the advice thank you. I just want to know does anyone have experience of someone becoming unselfish and how did it happen. Also if there are other “techniques” or things that someone selfish could do to change.