As per para 3.12 of Report of The Joint Committee on Business Process For GST on GST it is not possible to revise GST return filed under proposed GST Regime and all adjustment can be made for difference in invoice amount and Input Tax Credit (ITC) by way of Debit/Credit Note in GST return of subsequent Month. Related Provisions as per the report are as follows :-
3.12 Revision of Return
3.12.1 There would be no revision of returns.
3.12.2 All unreported invoices of previous tax period would be reflected in the return for the month in which they are proposed to be included. The interest, if applicable will be auto populated.
3.12.3 All under-reported invoice and ITC revision will have to be corrected using credit/debit note and such credit / debit note would be reflected in the return for the month in which such adjustment is carried out. The credit/debit note will have provision to record original invoice, date etc. to enable the system to link the same with the original invoice as also to calculate the interest, if applicable.Its format will be like the invoice.
3.12.4 There would be separate tables in the returns for reflecting those adjustments for which credit / debit notes are not required to be issued / issued. The interest, if applicable will be auto populated.