How Do I Make This Person Change?

The central reason people change their behavior is because they see the people around them changing. So psychologists sometimes call this social proof. One way to do that is to have several of their peers in contects adopt, which creates credibility for the idea and can also generate emotional excitement about getting on board. Havinga connections to existing adoptors and to people who are showing support for an idea keeps people engaged - it sort of sustains membership in the idea.