No partner of a DOT employee shall act as agent or attorney for anyone other than the United States in any DOT proceeding or matter in which such employee participates or has participated personally and substantially through decision, approval, disapproval, recommendation, rendering advice, investigation, or otherwise, or which is the subject of his or her official responsibility.

[Docket No. 82, 50 FR 2380, Jan. 16, 1985. Redesignated and amended by Doc. No. DOT-OST-2014-0140, 84 FR 15935, Apr. 16, 2019]