Dear Supervisor/HR rep,
I am writing to you today to officially submit my resignation from ABC Company effective XXX Date. After careful consideration, I have accepted another position in line with my long-term career goals.
Please be assured that I will do all I can to assist in the smooth transfer of my responsibilities before leaving. My experience at ABC Company has been rewarding, and I wish only the best for you and the organization.
I appreciate you respecting my choice to move forward in my career and ask that a counteroffer not be presented as this decision is not based on compensation.
Thanks again for having me as a part of your team.