To close a bank account on behalf of someone who has passed away, you must have legal authority to manage the account. It is often necessary that the property and financial affairs of a deceased person be supervised through a court process.The bank will not allow you to close it unless you have a letter of authorization from the probate court. In this video, we discuss an important aspect of estate planning: how to prevent your bank accounts from being frozen at the time of your death. Enclosed with this letter are the death certificate and my legal authorization as the executor. In these cases, you can try writing letters citing Illinois law, talking to managers or legal departments, etc. To get a bank or other agency to cooperate, but. To close a bank account after death, you must completely liquidate its funds. The simplified procedure for small estates begins with an affidavit. Specifically, Section 18.4 of the.