(a) In this chapter, "party" means a person who, by the terms of a multiple-party account, has a present right, subject to request, to payment from the account. Except as otherwise required by the context, the term includes a guardian, personal representative, or assignee, including an attaching creditor, of a party. The term also includes a person identified as a trustee of an account for another regardless of whether a beneficiary is named. The term does not include a named beneficiary unless the beneficiary has a present right of withdrawal.
(b) A P.O.D. payee, including a charitable organization, or beneficiary of a trust account is a party only after the account becomes payable to the P.O.D. payee or beneficiary by reason of the P.O.D. payee or beneficiary surviving the original payee or trustee.