Many companies and organisations operate under the guidance of a board of directors. Members of the board often serve specific terms and vacate their positions only when their term ends. A board member might also resign his position before the end of his term because of retirement, sickness, a business conflict or relocation. A departing board member should write a formal letter of resignation to announce his departure.
Open the letter with a salutation, such as, "Dear XXX Company Board Members."
Write a statement of your intent to resign, such as, "The purpose of this letter is to inform you of my intent to resign as a XXX company board member. Effective March 31 of this year, I hereby relinquish all my rights, responsibilities and privileges as a board member."
Express your gratitude for the opportunity to serve on the board and your reason for resigning (optional). Consider wording such as this: "I have thoroughly enjoyed my tenure as a board member over the last 25 years and I'm thankful for the opportunity to serve. However, as I approach retirement age..."
End the letter with a farewell, such as, "I wish you all the best as you lead XXX Company."
Close with a phrase such as, "Respectfully Yours" or "Sincerely Yours."