How to Enter Debit Note in GSTR 1 for Debit note issued due to Revision of GST Rate Difference.

Hi, 

Client has issued invoice in the month of November 2021 by charging GST rate @ 12%. However such rate has been changed to 18% from October 2021. At present client has issued debit note for 6% Additional GST . How can i Record such debit note in the GSTR 1 . As there is no change in taxable value only GST Difference is charged in the note. So can not able to upload the same in Debit notes table in the portal. Kindly guide how to record the same in the GSTR 1 in GST Portal. As we can not add only GST Amount in debit note table in the portal.