Wash. Rev. Code § 30A.49.080
A resulting state or national bank shall be the same business and corporate entity as each merging state or national bank or as the converting state or national bank with all property, rights, powers and duties of each merging state or national bank or the converting state or national bank, except as affected by the state law in the case of a resulting state bank or the federal law in the case of a resulting national bank, and by the charter and bylaws of the resulting state or national bank.
A resulting state or national bank shall have the right to use the name of any merging state or national bank or of the converting bank whenever it can do any act under such name more conveniently.
Any reference to a merging or converting state or national bank in any writing, whether executed or taking effect before or after the merger or conversion, shall be deemed a reference to the resulting state or national bank if not inconsistent with the other provisions of such writing.
RCW 30A.49.080