A vendor can break ties with a business or shipping company with this professional goodbye letter.
This is just a quick note to let you know that I will be leaving {Company} on {date}. It has been such a pleasure doing business with you for the last {number} years and I didn't want you to be offended when you called us up and had to talk to someone new!
My replacement's name is {Name} and you can email {him/her} at {email address}. {He/she} is a wonderful colleague and would be happy to work with you on the company's next project.
I'm not sure yet what the future will hold for me, but I hope that our paths cross again, and that we find ourselves doing business together in the future.
