(Name, Company, Address)
Today is the mark of your third anniversary as a member of the Go company. I would like to take this opportunity to thank you for these past three years of your loyalty and good workmanship to the company.
I know that the growth and success of my company is largely dependent on having a strong and capable staff member, like you. Your contributions to the industry are very much appreciated.
I am hoping that you will remain with the company for many years to come and would like to offer my congratulations.