1. Listen: First, try to understand the possible reasons behind the roommate change. Maybe they don't adapt to the new environment or are influenced by the outside world. Talk frankly with roommates and listen to their feelings and thoughts.
2. Direct communication: communicate frankly with roommates and express their observation and concern about their changes. Point out the possible negative effects of vanity behavior and remind them to keep simple and true values.
3. Remind values: share your values and opinions with roommates and encourage them to re-examine their behaviors and values. Remind them to pursue inner qualities and really important things, not just external materials.
4. Provide support and advice: If your roommate is vain because of uncertainty or anxiety, you can provide support and advice. Help them build a healthier self-identity and self-esteem, and encourage them to explore and cultivate their inner self-worth.
5. Encourage positive behavior: Encourage roommates to participate in some more meaningful and positive activities, such as volunteering, participating in community service or sharing knowledge and experience with others, so as to help them pay attention to their intrinsic value again.
6. Seek support network: If the change of roommates brings you problems or unpleasant influences, you can seek help and support from other friends, counselors and other support networks. They can give you more advice and guidance.
Remember, dealing with roommate relationships requires patience and understanding. Try to communicate with roommates in a positive way to help them return to their pure and true self.