(City, State, Zip)
Dear (Supervisor name):
This letter is to notify you that I will be terminating my employment with (Company Name) effective (date). I have been offered a position in another organization and have decided to take this career opportunity.
I am grateful for the rewarding opportunity I have had at (Company Name), serving as (position), and especially working with you. My decision was not easy, but it is the right one for me as I advance toward fulfilling my goals.
I will focus my efforts until my ending date on assisting in wrapping up any outstanding projects and smoothly transitioning my responsibilities.