Writing a letter of resignation to a board of trustees you are serving on may be a stressful task. However, it is likely that you will be relieved after it is done, and even more relieved if you do it right. Doing it right means resigning with grace and tact, so there are no ill feelings on either side. Leaving an important professional commitment is never an easy decision, but if you are sure you are making the right decision, you can leave the position in a positive manner.
Use a professional business letter format. Employ all the standards of business letter etiquette. See the resources section for a full review of business letter etiquette and a sample of templates you can download and use.
Maintain a polite and professional tone at all times. Though your reason for resigning may be because of conflict or an unhappy experience during your time as a board member, this letter will forever be attached to your professional life. Bowing out gracefully will assure you are not burning any bridges.
Give some insight as to your reasons for resigning. If the issue is personal, you do not have to offer details you are uncomfortable giving. If the issue has to do with your health, you have the right to maintain your confidentiality and not divulge any medical information. In both of these situations, it is enough to say that you are resigning for "personal reasons", a "family emergency" or because of "health reasons" without going into too much detail.
Express your regrets about your resignation. Though resigning may make you ecstatic, you do not want to communicate that you are happy about leaving the position. Instead, you should convey the respect you have for the work the board does and for its members. Expressing regret at the prospect of resigning shows humility and grace.
Close with good wishes for the future of the board. Similar to expressing regrets about resigning, this courteous statement will breed goodwill and deflect and personal issues other members of the board may have with your resignation. A generic good luck may sound insincere, so you may want to write a few specific hopes you have concerning the direction of the board or a particular project.