1 Pa. Code § 31.26
In a proceeding where an attorney has filed a submittal on behalf of a client or has filed an appearance under § 31.24(b) (relating to notice of appearance), a notice or other written communication required to be served upon or furnished to the client shall also be served upon or furnished to the attorney (or one of the attorneys if the client is represented by more than one attorney) in the same manner as prescribed for his client, notwithstanding the fact that the communication may be furnished directly to the client.
1 Pa. Code § 31.26
This section cited in 1 Pa. Code § 33.33 (relating to effect of service upon an attorney); 7 Pa. Code § 131.13 (relating to service); 22 Pa. Code § 121.9 (relating to administrative loan collection review procedures); 34 Pa. Code § 111.12 (relating to filing, service and proof of service); 34 Pa. Code § 111.14 (relating to motions to quash); 34 Pa. Code § 131.11 (relating to filing, service and proof of service); 34 Pa. Code § 131.32 (relating to petitions except petitions for joinder and challenge proceedings); 37 Pa. Code § 171.27 (relating to service on attorneys); 40 Pa. Code § 17.4 (relating to legal representation); 52 Pa. Code § 1.55 (relating to service on attorneys); 52 Pa. Code § 1001.53 (relating to service on attorneys); and 61 Pa. Code § 702.21 (relating to representation).