This guide offers tips for writing acknowledgement letters to families for donations made in memory of a loved one. If you are returning to update your pledge, or honor or memorialize someone special, thank you.To PO Box 50187, Lighthouse Point, FL 33074. What do you need to include in your donation acknowledgment letter? Note: This form must be completed and submitted to the school on an annual basis, regardless of the chosen option, WITHIN 10.