[NAME, COMPANY AND ADDRESS, ex.
John Smith
XYZ Inc.
1234 First Street
Suite 567
Anycity, Anystate  85245]
 

Dear [NAME, ex. John Smith], 

I was delighted to hear that you had accepted the position of [DESCRIBE POSITION, ex. Sales Manager].

I have every confidence that you will enjoy success and prosperity in that position. I believe you have earned the respect of your colleagues and that the firm as a whole will benefit from your appointment. 

As always, please let me now if I can assist you in any way to make the transition seamless.

Best regards,
 

[YOUR NAME, ex. Jill Jones]