In an action prosecuted or defended by an executor, administrator, trustee of an express trust, or a person expressly authorized by statute, costs shall be recovered as in an action by or against a person prosecuting in his or her own right, but such costs shall be chargeable only upon or collected of the estate of the party represented, unless the court shall direct the same to be paid by the plaintiff or defendant personally, for mismanagement or bad faith in such action or defense.
RCW 4.84.150
Actions by and against personal representatives, etc.: Chapter 11.48 RCW.