210 Pa. Code § 120
Any counsel filing papers required or permitted to be filed in an appellate court must enter an appearance with the prothonotary of the appellate court unless that counsel has been previously noted on the docket as counsel pursuant to Pa.R.A.P. 907(b), 1112(f), 1311(d), 1514(d), or 1602(d). New counsel appearing for a party after docketing pursuant to Pa.R.A.P. 907(b), 1112(f), 1311(d), 1514(d), or 1602(d) shall file an entry of appearance simultaneously with or prior to the filing of any papers signed by new counsel. The entry of appearance shall specifically designate each party the attorney represents, and whether the attorney is entering an appearance as substitute or additional counsel. The attorney shall file a certificate of service pursuant to paragraph (d) of Pa.R.A.P. 121 and to Pa.R.A.P. 122. If an attorney enters an appearance as substitute counsel for a party, the original counsel of record for that party may withdraw by praecipe, without filing an application for permission to withdraw.
210 Pa. Code § 120