I often have clients who ask me if I can change someone they know (not necessarily themselves). My answer in the past has been that I can only change them, not other people. My new answer is, that by creating the habit of reacting differently toward that other person, you can indeed change them. For example, if the other person has a habit that you don't like (say nagging for example), you can change that person by continually reminding them that you will not accept their behavior when they do it; or by just refusing to speak with them when they act that way (not engaging). So, by forming their own new habits, clients can indeed change other people!