Congratulations on your Retirement
Congratulations on your on your retirement! It was with mixed feelings that I __(heard/read)__ the announcement of your retirement. Though I am very happy for you that you will now have the time to enjoy other pleasures in life, I am so sad to see you go. You are going to be greatly missed here.
It has been a privilege to be able to work with you over the past __(#)__ years, __(Name)__. I`ve come know you as an honorable person with a high degree of integrity. We`ve all appreciated that you were always ready to help someone in need with a smile and a great sense of humor. I know I speak for many others when I say that you will be solemnly missed.
It is evident that you have cared about your __(fellow co-workers/colleagues/etc.)__. Your shoes will be really hard to fill. But don`t you worry about that, we`ll find a way to get along here. You just concentrate on embracing that new life of leisure you have ahead of you.
I wish you the very best, __(Name)__. Once again, congratulations on your retirement. It has been a real pleasure working with you!