(a) Before final judgment. At any time before the judgment the party restrained or enjoined may apply to the judge of the court in which the action is brought, to vacate or modify the same. The application may be made upon the petition and affidavits upon which the restraining order or injunction is granted, or upon affidavits on the part of the party restrained, with or without answer.

(b) After final judgment. Any interested party, including a party subsequently acquiring an interest in the subject matter of the injunction, may file a petition in the same action to have a judgment of permanent injunction vacated or modified. The petition shall be verified, filed in the court from which the judgment issued, and shall state that there has been a change in conditions rendering the injunction unnecessary or partially unnecessary and that petitioner’s interests are being adversely affected. The changed conditions shall be stated in reasonable detail. The procedure pertaining to original civil actions shall be followed. If the judge, after hearing, finds that the petition was not filed in good faith, the judge shall assess the expenses and reasonable attorneys’ fees against the petitioner for those parties who have defended against the application, the same to be collected as costs in the action.