You don't need to write any letter, additionally, no one would entertain withdrawal on the basis of a letter, the mandate should be clear. I am of sound mind and capable of making this affidavit.Use this letter to tell a company that you are taking away your permission for the company to take automatic payments out of your bank account. Contact your bank for a power of attorney form. Authorization letters are formal letters that empower somebody else to take actions on your behalf. This is called "revoking authorization. Instructions are at the top of this form. 4. Take card not present payments with ease. A court must grant someone else the power to withdraw money and close the account. Does my foreign entity need to file an application for registration?