I have no idea why a bank representative would advise you to get a whole new EIN for an existing trust after your mother passed away with respect for the trust presently in effect unless under her trust there is a provision for some new trust to be created under it. If so, the new trust will need to have its own EIN for tax purposes.I suggest that you consult with a Wills and trust attorney about the terms of your mother's trust in effect when she passed.