The letter must be mailed within 30 days after the appropriate federal banking agency approves such branch. Use this interactive form to draft a simple letter to your bank giving them permission to disclose information about your account to a third party.Questions pertaining to this application should be directed to the Corporate Activities Section at (217) 785-2900. Learn to delegate your financial duties safely with our guide on authorization letters for transactions. Mention your name and a short description of who you are. Contact your bank for a power of attorney form. Mention in the letter why you are authorizing somebody else to claim the money. And it helps if you provide a short justification. Address the recipient appropriately; if it's an authorization letter to bank, mention the bank's name and address. "My dad died and I'm executor in the Will.