Dear Seth Farley,
This letter is to share my warm wishes and congratulations to you on your retirement.
I still remember the day you joined as (Position name) in our company and since then how much you have grown individually and professionally. While, you have been a great colleague and a friend with whom I have not only shared various work assignments, but also moments of leisure and fun. I hope that you are equally excited for the time to come and adventures that are ahead of you.
I also want you to know that we will miss you and we will forever remember your dedication, hard work, accomplishments, and personal integrity. People and teammates like you are not only hard to find, but also make work and the workplace joyful and positive.
We wish all the happiness and blessings for your future and once congratulations on achieving this milestone.