Dear Jake,
I just wanted to write you a note to tell you how much I've appreciated everything you've done for me. You were willing to take a chance on me when others wouldn't, due to my inexperience. Not only that, but you stuck by me as I learned and made mistakes.
I'm happy that you've found a new position with greater responsibilities. You deserve it. But I'm sad to see you go. You were more than a boss to me; you were a mentor and a friend. I will always value your advice, and will remember the lessons you have taught me. I remember the first time I missed deadline, and help up the whole paper. I was scared you would fire me. Instead you were supportive and understanding.
I hope we can stay in touch, professionally and personally. I have the highest respect for your talent and leadership skills. You have the ambition and acumen to be wildly successful. I hope you and Denise will find personal satisfaction in Albany as well. I hear it's a nice city. If there's ever anything I can do for you, please don't hesitate to ask.
All my best,
Tanya