In your letter, you should politely decline the applicant. In this article, we'll talk you through what's included in a rental application denial letter and even give you a free template to use.Download a customizable rental application rejection letter template for landlords or property managers to professionally notify applicants. Add your name, current return address at the top with your rental application date. If you are providing conditions for approval, list them in the letter after explaining why the application has yet to be approved. A denial letter is a formal way of informing a potential tenant that their application or tenancy has been denied.