1 Pa. Code § 35.31
If a party who has been granted intervener status actually presents evidence during the course of an administrative hearing, the only way for that intervener to withdraw its appearance would be by leave of the presiding officers. Pennsylvania Association of Home Health Agencies v. Insurance Department, 547 A.2d 824 (Pa. Cmwlth. 1988).
This section cited in 1 Pa. Code § 31.3 (relating to definitions); 7 Pa. Code § 131.11 (relating to time); 7 Pa. Code § 131.14 (relating to interveners); 7 Pa. Code § 179.17 (relating to intervention); 25 Pa. Code § 1021.81 (relating to intervention); 28 Pa. Code § 301.7 (relating to fair hearing); 34 Pa. Code § 131.32 (relating to petitions except petitions for joinder and challenge proceedings); 40 Pa. Code § 17.13 (relating to protests/intervention procedure); 49 Pa. Code § 19.33 (relating to intervention); 49 Pa. Code § 31.103 (relating to applicability of other laws and rules); 49 Pa. Code § 31.115 (relating to disciplinary sanctions); 52 Pa. Code § 5.75 (relating to notice, service and action on petitions to intervene); 52 Pa. Code § 1005.35 (relating to notice, service and action on petitions to intervene); 58 Pa. Code § 493a.12 (relating to intervention); 61 Pa. Code § 703.2 (relating to petition content); 67 Pa. Code § 441.3 (relating to permit application procedure); and 67 Pa. Code § 491.6 (relating to notice and conduct of hearing).