1. Honest communication: Have a deep and candid conversation with your biological sister, clearly expressing your feelings and the reasons for deciding to sever ties. Ensure that both parties have the opportunity to express their thoughts and feelings, but also maintain their own positions.
2. Clear boundaries: After communication, clearly define the boundaries of your new relationship. This may include reducing or stopping direct communication, avoiding joint activities, etc. Ensure that these boundaries are acceptable and understandable to both parties.
3. Seeking support: Breaking off ties with one's own sister can be a difficult decision, so seeking support from family, friends, or professional counselors is crucial. They can provide emotional support, understanding, and advice to help you get through this difficult time.