It has been an amazing four years for me here at ________________. I started off with you as a temporary employee, and then you graciously took me on full time. I want to let you know how much I appreciate all of the learning opportunities you extended to me during the time I have worked with you. You have always been a fair and kind employer. The decision to leave and take a position with ______________was a difficult choice to make. I will miss you greatly, and I’d love to keep in touch. My new email address is _________________.
With best regards,
(YOUR NAME HERE)