With regard to actions for the revocation of an original administrative disposition or an administrative disposition on appeal that are pending at the time this Act comes into effect, the provisions then in force continue to govern, notwithstanding the provisions as amended by this Act that provide that one of the parties to the relevant legal relationship is to be the defendant; provided, however, that the court may, upon petition by the plaintiff, permit by ruling the change of the action to a public law-related action.