Some other relevant sections :

This note has so far discussed the provisions of Chapter XVIII of the model GST Act, which are the main provisions dealing with appeals. However, some other provisions are also relevant, which are briefly discussed below.

Section 128 of the GST Act provides that various proceedings such as assessment, adjudication, review, revision, appeal, etc. shall not be invalid merely by reason of any mistake therein, if such proceedings are in substance in conformity with the Act or any earlier law. For details, see Appendix.

Section 129 of the GST Act provides thatany authority who has passed any decision or order (etc.) may rectify any error which is apparent from record in such ndecision or order (etc.) within a period of six months, after putting the affected person(s) to notice. For details, see Appendix.

Section 27 of the model IGST Act makes certain provisions of the GST Act  applicable to like matters in respect of IGST. This includes the provisions relating to appeals and review. Thus, whatever is discussed hereinabove in relation to appeals and review under CGST, will also apply in respect of IGST. For details, see Appendix.