Assuming your bank is in Mississippi, that's a Mississippi question, but there is no Mississippi forum.
The generic response would be that it depends on what the will or state statute says about jointly appointed personal representatives being allowed to act independently or being required to act together. If there is no such legal authority then the conservative position for the the bank is that both parties must be present and sign in.
The one thing that is universally true is that, in the absence of state law mandating the action, there is no way a bank employee is going to be involved.
In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.