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

Dear [NAME, ex. John Smith],

It was a pleasure, albeit not a surprise, to hear of your promotion to [POSITION, ex. Director of Sales] at [FIRM, ex. XYZ Inc].  Congratulations!  I am certain you will meet with much success at your new position and I look forward to congratulating you in person.

Best regards,
 

[YOUR NAME, ex. Jill Jones]