[Your letterhead, if desired; if not, your return address]
[Date of letter—month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
I am writing on behalf of my daughter, Sue, to apologize for the way she treated your daughter, Beverly, when they were playing on the playground yesterday. Sue says that she knows what she said to Beverly was hurtful and wrong, and she very much regrets acting that way. She and I both want to apologize to Beverly and to you. We also want to let you know that in the future, Sue promises not to act this way again.
Sue would like to apologize to Beverly in person, so please let me know if both of you can come over to our house sometime soon. We really hope that we can put this incident in the past and move forward from here. Thank you for listening, and thank you for accepting Sue’s apology.
[Sender's first and last names]