(a) If a petitioner dies or is otherwise unable to pursue the petition, the action may be completed upon substitution of a proper party.
(b) A motion for substitution shall be filed by the proper party within 90 days after the death of the petitioner or other disabling event. [58 FR 61992, Nov. 23, 1993, as amended at 68 FR 69301, Dec. 12, 2003]