Wash. Rev. Code § 11.36.010
Parties disqualified—Result of disqualification after appointment—Nonresident personal representatives permitted
(1) The following persons are not qualified to act as personal representatives:(a) Corporations, limited liability companies, and limited liability partnerships, except as provided in subsections (2) through (4) of this section;(b) Minors;(c) Persons of unsound mind;(d) Persons who have had letters testamentary or of a…