Section 1. Amendments of Pleadings and Supplemental Pleadings. - Before a pleading can be amended or supplemented, the pleader shall file a motion for leave attaching therewith the proposed amended or supplemental pleading. Except as provided in the following section, such leave to amend will be allowed or denied by the Commission as a matter of discretion.
If the amendment will substantially enlarge or modify an application or petition, the Commission, after granting leave, shall require applicant or petitioner to comply with the requirements in Rule 6, if the application or petition is covered by said rule, and to republish the notice of hearing on the amended application or petition.
Section 2. Amendments of Complaints and Petition. - Complaints may be amended once as a matter of right before the respondent files a responsive pleading thereto. The same rule applies to petitions which implead a respondent. After the filing of such responsive pleading, amendments of pleadings or the filing of supplemental pleadings may be made only upon leave of the Commission.
Section 3. Amendments to Conform to the Evidence. - When, at a hearing, issues not raised by the pleadings are introduced by express or implied consent of the parties, they shall be treated in all respects as if they had been raised in the pleadings. Such amendment of the pleadings as may be necessary to cause them to conform to the evidence and to raise these new issues may be made upon motion of any party at any time during or after the hearing. If evidence upon new issues is objected to on the ground that it is not within the issues raised in the pleadings, the Commission may allow the amendment of pleadings and such evidence to be received, when it appears that the presentation of the merits of the proceeding will be served thereby without prejudicing the public interest or the rights of any party.
Section 4. Withdrawal. - A party desiring to withdraw an application, petition, or complaint filed with the Commission shall file a motion to withdraw such application, petition, or complaint stating therein the reasons for the withdrawal. Such motion will be granted or denied by the Commission as a matter of discretion.