(1) The commission may at any time, and from time to time, after notice, and after opportunity to be heard as provided in the case of complaints, rescind or amend by order any decision made by it.
(2) Any order rescinding or amending a prior order or decision, when served upon the public utility affected and the other parties to the proceedings, shall have the same force and effect as is provided in this act for original orders or decisions. However, no such order shall affect the legality or validity of any acts done by the public utility or others before service upon it or them of the notice of the change.