John Hertog and Mike Olver, two prominent Seattle probate attorneys, provided me with the following information. Any errors are mine.

"Personal Representative" is a term of art that describes someone who is an executor, administrator of an estate, and also a guardian or trustee. It is equivalent to the term "fiduciary". It is proper to use the term Personal Representative in legal papers to describe any person managing a probate estate. RCW 11.02.005 sets out some definitions, although these are not uniformly illuminating.

An "Administrator" is a person named to manage an intestate estate, and receives letters of Administration

An "Executor" is a person named in a will to administer a probate estate. Upon appointment an executor receives letters testamentary.

An "Administrator With Will Annexed" is appointed when the executor(s) named in the will are not suitable or available to serve. Upon appointment the Administrator WWA receives letters of administration.

An "Administrator de bonis nom" (with or without will annexed) is the title of a person appointed to succeed an appointed administrator who has not completed the probate. The term is derived from Latin for the phrase "the goods not administered".

It is still considered proper to refer to a woman acting as PR as "Administratrix" or "Executrix".

RCW 11.36.010 sets out who is qualified to act in the above capacities. Generally, individuals, banks, trust companies, and Personal Service corporations composed of attorneys may be appointed. Corporations, including non-profit corporations, are not eligible.

RCW 11.88.150 (2) allows a guardian under certain circumstances to administer the intestate estate of the deceased IP by converting the guardianship to a probate using the same cause number. This statute does not re-state the limitation on corporations to so act, is a more recent enactment than 11.36.010 and theoretically provides an exception to the exclusion of corporations.

A "Special Administrator" is sometimes appointed to manage all or parts of a probate estate when, for some reason, there is delay in appointing or empowering a PR. Guardians are sometimes appointed Special Administrator if there is delay in locating and filing a will or there is a contest over who should be the PR. Duties are limited to those things necessary to preserve the estate pending appointment of a PR. The statute describing Special Administrators is RCW 11.32 .  A Special Administrator is  generally not referred to as a PR.