Write a Graceful Resignation Letter

Act as a professional communications coach. I am resigning from my role as [CURRENT_ROLE] at [COMPANY_NAME] after [TENURE]. My relationship with my manager is [RELATIONSHIP_TYPE] and I want to leave on the best possible terms. Write a resignation letter that: gives the required [NOTICE_PERIOD] notice, expresses genuine appreciation for specific opportunities or people, keeps the reason for leaving appropriately brief and professional, and offers a constructive transition. Tone should be warm, dignified, and bridge-preserving.