Ask the company or institution (like a bank) that has the property if they have an Affidavit for you to use. Begin the probate process.Make the process of opening an estate account simple and straightforward with this stepbystep guide. The process of claiming a bank account after death varies based on a number of factors. Here's how to claim a deceased person's bank accounts. To start the process of obtaining a letter of administration, you must fill out Form DE150. What you may need ; Trust. Accounts with arrangements to hold the assets in a trust. What Documents Do I Need for a Letter of Administration? Now that you have your estate tax ID number, you will need to go to a bank of your choosing to set up the estate account.