RCW 11.48.040: Not chargeable on special promise to pay decedent's debts unless in writing.

No personal representative shall be chargeable upon any special promise to answer damages, or to pay the debts of the testator or intestate out of his or her own estate, unless the agreement for that purpose, or some memorandum or note thereof, is in writing and signed by such personal representative, or by some other person by him or her thereunto specially authorized.