Call or email the person who made you the written offer. Say that you're following up and want to make sure they received your reply accepting the position.Learn how to write a professional job offer letter acceptance mail reply with joining date with an easy format and practical samples. Search 113 Careers available. The Port Authority of New York and New Jersey Careers. I am writing to confirm my acceptance of your employment offer on April 20 and to tell you how delighted I am to be joining XYZ Corporation in Chicago. Go to the same website where you applied. The starting paragraph should always begin with your acceptance of the job offer letter.