1 Pa. Code § 31.21
An individual may appear in his own behalf. A member of a partnership may represent the partnership, a bona fide officer of a corporation, trust or association may represent the corporation, trust or association, and an officer or employe of another agency or of a political subdivision may represent the agency or political subdivision in presenting any submittal to an agency subject to these rules. Parties, except individuals appearing in their own behalf, shall be represented in adversary proceedings only under § 31.22 (relating to appearance by attorney).
1 Pa. Code § 31.21
This section cited in 1 Pa. Code § 31.23 (relating to other representation prohibited at hearings); 4 Pa. Code § 89.26 (relating to representation); 4 Pa. Code § 607a.8 (relating to representation); 7 Pa. Code § 131.12 (relating to appearances); 7 Pa. Code § 179.63 (relating to representation before the Commission); 12 Pa. Code § 11.5 (relating to appearance before the Department); 25 Pa. Code § 1021.21 (relating to representation); 28 Pa. Code § 1111.8 (relating to rights of the appellant); 28 Pa. Code § 1113.2 (relating to administrative appeal procedures); 28 Pa. Code § 1230.26 (relating to representation); 34 Pa. Code § 131.54 (relating to manner and conduct of hearings); 34 Pa. Code § 131.58 (relating to informal conferences); 34 Pa. Code § 131.59 (relating to mediation); 34 Pa. Code § 131.59a (relating to voluntary mediation); 34 Pa. Code § 131.59b (relating to mandatory mediation); 34 Pa. Code § 131.60 (relating to resolution hearings); 37 Pa. Code § 197.9 (relating to appearances); 49 Pa. Code § 43b.302 (relating to representation in formal proceedings); 52 Pa. Code § 1.21 (relating to appearance); 52 Pa. Code § 1001.21 (relating to appearance); 58 Pa. Code § 499a.1 (relating to appearance in person); and 61 Pa. Code § 702.21 (relating to representation).