Question: how do you say goodbye to a coworker who is leaving the company?
Answer: “Congratulations on your new job. ... 
“Congratulations on a job well done! ... 
“I've learned a lot from working with you over the years. ... 
“It was an honor to work with a coworker who was committed to their success and their coworkers. ... 
“We will remember you with warm thoughts and memories.