Complete the information requested on the Mail-in Claim Form page. The bank will not allow you to close it unless you have a letter of authorization from the probate court.You should also make a list of what the Decedent owned at the time of death (such as bank accounts, house, stocks, etc.). The first and foremost thing you must do to close a bank account upon the death of a loved one is to inform the bank of this death. The BMO Alto Letter of Direction describes how an authorized representative would like BMO Alto to settle the decedent's account. Closing Deceased Accounts. A bank usually cannot close a deceased account until the person's estate has been settled and closed, typically through probate. To close a bank account on behalf of someone who has passed away, you must have legal authority to manage the account. My dad passed away two months ago. Got the death certificate in hand and went to the bank to close his account.