Thankyou letters should begin with a statement thanking the vendor for their service. Date Certificate Needed.30 days advance notice is required. Learn how to write an employee appreciation letter with these templates and examples. Download the template for free (PDF or Word). Beyond a professional and courteous 'Thank you for your offer, which I am pleased to accept', there is no need for anything else. The message of appreciation should stand alone. Be brief, warm, and sincere. Hats off to the wonderful construction workers, who have been and are working on the other end of Riverside Drive where I live, who are dedicated, responsible. Dear Potential Instructor,.