Sample letter for donation request from a company. How to write a letter requesting sponsorship. A final warning letter is the last letter that a company writes for its employee to make a positive change before adverse actions such as legal action or dismissal are taken against the involved employee for advocating some negative behavior that is unacceptable to the company. Your letter must convince the sponsor that its worth contributing. The candidate could have written in to request for an internship position with some company earlier and has just received the good news of its successful placement.