Resignation letters should use the formal greeting: "Dear". The first sentence in the letter should state that you are resigning and when.Here are 3 examples that you can use for resignation letter as Assistant Professor -. Here are 3 examples that you can use for resignation letter as Visiting Assistant Professor -. Include the last date of your employment in your email. Provide your employer with as much notice of your resignation as possible. Resignation letters are professional courtesies that extend your professionalism, even in the last days of current employment. (For example, "I regret to inform you that I will be resigning from my position, effective immediately. For all Employees Except Adjunct Faculty. Date. TO: Name of Employee.