The Labour Court, acting of its own accord or on the application of any affected party may vary or rescind a decision, judgment or order-
erroneously sought or erroneously granted in the absence of any party affected by that judgment or order;
in which there is an ambiguity, or an obvious error or omission, but only to the extent of that ambiguity, error or omission; or
granted as a result of a mistake common to the parties to the proceedings.