How do you write a graceful resignation letter when you’re leaving under unfortunate circumstances? Maybe your job is seriously damaging your health and well-being, or you even suspect your organization is behaving unethically — or illegally. Whatever the situation, you don’t want the substance of your letter to come back to haunt you, so don’t point fingers or level accusations. You need your current boss or HR department to be able to provide at least a neutral reference if future employers contact them. So, offer a genuine compliment in your letter, such as how much you’ve learned during your time at the company. Then give a believable reason for your departure. It doesn’t have to be the primary reason, but it should be truthful. For example, you might say, “I’ve realized I can best fulfill my goals by redirecting my career toward sales and marketing.” Being professional on your way out preserves your reputation, which will be critical to landing your next job.
Adapted from "When You Should Quit Your Job Without Having Another One Lined Up," by Priscilla Claman