My sisters will

Please accept my condolences on the loss of your sister. As for your question, I can't actually tell whether your late sister had a valid Will, because you mention that it named an Executor but you also state that it named your other sister as a power of attorney agent and you to make health care decisions, and a normal Will would not do either of those two things. If your sister does not have a valid Will in the first place, which may well be the case if she tried to do her own Will and did not get good legal advice when she was preparing the document, then state intestacy law will apply to her probate assets, and not the document in question. That said, assuming for now that your sister does have a valid Will that names you and your other sister as beneficiaries and your other sister as Executor, the Will must be offered for and admitted to probate before it will become legally binding. That's not a requirement of any bank; it's a requirement of state law. A Will that has not been admitted to probate isn't doing anything legally. The probate process is how you prove that a Will is valid and should be given effect, and it is required before any Executor is appointed and before the Will can actually direct the disposition of a deceased person's assets. So no, a bank will not accept an unprobated Will as valid. The only way you can get access to a bank account that was owned by a deceased individual if you are not either a joint owner with right of survivorship or a designated beneficiary on that account is to have the person's probate estate opened through a probate or an estate administration and to have an Executor or Administrator appointed. Your sister who is named as Executor should consult an experienced probate attorney. Show that attorney the document you believe to be a Will and see if it appears to qualify as a Will. If it does, then your living sister should have the attorney help her offer it for probate. If not, then your late sister's heirs (which might be you and your other sister but may not be- I don't have enough information to be able to tell from your post) will need to see about having her estate opened for administration or whether a Petition for No Administration Necessary might be a good option. Best wishes to you.