(a) Complaint and notice of hearing. The Commission may, at any time, amend the complaint and notice of hearing in any proceeding. If the Commission so amends the complaint and notice of hearing, the Administrative Law Judge shall adjust the scheduling of the proceeding to the extent necessary to avoid any prejudice to any of the parties to the proceeding. Upon motion to the Administrative Law Judge and with notice to all other parties and the Commission, the Division of Enforcement may amend a complaint to correct typographical and clerical errors or to make other technical, non-substantive revisions within the scope of the original complaint.

(b) Other pleadings. Except for the complaint and notice of hearing, a party may amend any pleading once as a matter of course at any time before a responsive pleading is served or, if the pleading is one to which no responsive pleading is permitted, he may amend it within 20 days after it is served. Otherwise a party may amend a pleading only by leave of the Administrative Law Judge, which shall be freely given when justice so requires.

(c) Response to amended pleadings. Any party may file a response to any amendment to any pleading, including the complaint, within ten days after the date of service upon him of the amendment or within the time provided to respond to the original pleading, whichever is later.

(d) Pleadings to conform to the evidence. When issues not raised by the pleadings but reasonably within the scope of a proceeding initiated by the complaint are tried with the express or implied consent of the parties, they shall be treated in all respects as if they had been raised in the pleadings.