Leave
Dear Robert,
I regret to inform you that I decided to resign from my present position as Associate Software Engineer with effective from 12/21/2013.
Thank you for giving me a chance to learn and to gain the valuable experience in Fidelity. I hope my resignation would not cause you much inconvenience.
Thank you for your kind attention and would appreciate if you could let me have a reference letter before I leave.
Yours Faithfully,
Wolfe Yu.