Articles 801 through 804 apply to the substitution of a legal representative of any party other than a deceased person, and to the substitution of the successor of any legal representative appointed by a court of this state, except that the term “legal successor”, as used therein shall be considered as referring to such legal representative, or successor, as the case may be.

When an action has been commenced by a proper representative on behalf of an incompetent person and such person thereafter becomes competent, the authority of the representative shall continue until substitution is made in accordance with the provisions of this article.