Debit note against export made with payment of GST

You are permitted to issue a debit note for an export invoice to account for upward price revisions. To claim a refund for the additional IGST paid via this debit note, ensure the debit note is properly reported in your GST returns (GSTR-1/3B) and file a refund application (Form RFD-01) on the GST portal, provided export proceeds have been realized for both the original invoice and the debit note.