law: 95. Revision.-
  The Administrator or the Collector may, at any time, either on his own motion, or on the application of any party, can for the records of any proceedings before any revenue officer subordinate to him for the purpose of satisfying himself as to the legality or the propriety of any order passed by such revenue officer, and may pass such order in reference thereto as he thinks fit:
  Provided that he shall not vary or reverse any order affecting any right between private persons without having given to the parties interested notice to appear and be heard.