Ill. Admin. Code tit. 92, § 1225.210
a) The Commission's Tariff Concurrence (Specific Concurrence) form or its Tariff Concurrence (General Concurrence) form shall be used in giving to carriers subject to this Part concurrences in tariffs (including supplements or loose-leaf page amendments thereto) which are issued and filed by such carrier or their agents and in which the carriers giving concurrences are participants.