Revised Bill to be issued on change of HSN Code?

No you can raise debit note against the same invoice

Ok, in this case we can raise the GST credit for entire taxable value+12% GST, then issue fresh invoice taxable value+18% , this treatment is correct or not?

Issue credit note as per the relevant section. Whether credit note issue is allowed for such circumstances. If yes then if no then don't.

Issue a debit note then.

Altamush zafar i already section of GST debit note and GST credit note, but there is no clarity about this,

The sections are very clear.

Since you yourself are a CA student I want you to apply the section yourself.

After reading that section,i think only debit note is allowed in this case, isssued of credit note and then issue fresh invoice is not possible in this case, am i right?

Yes that is correct....

Agree

A registered supplier of goods or services or both is mandatorily required to issue a tax invoice. However, during the course of trade or commerce, after the invoice has been issued there could be situations may arise like:

1– the taxable value or tax charged in that tax invoice is found to exceed the taxable value or 2-tax payable in respect of such supply (Where Declared Value more than Actual Value) / (Rate of tax charged higher than rate applicable) or

3– where the goods supplied are returned by the recipient, or where goods or services or both supplied are found to be deficient (Quantity received less than Declared Quantity) / (Quality is not as per specifications)

4– Any other similar reasons,

in credit note definition there is 4 the conditions is Any other similar reasons, this 4 th conditions is confusing about issue give in the my query, i need opinion on this issue

Credit or a debit note serves the purpose of accounting adjustment to settle the correct amount of value and tax for any invoice already issued in the same or earlier period.

As per Section 34(1) talks about the credit Note & Section 34(3) talks about the Debit note.
So you can issue the credit note for the said invoice & can issue the fresh invoice for the same .
Or can issue the debit note for the balance 6% .
So in my view both the method are correct.

Note : in many instances , the recipient insist to issue the debit in such situation because on the basis of this purchase bill he might have already issued the sale bill .
So it's depends on Recepient also.

In my view since the HSN in bill was also wrongly mentioned , the credit note must be issue & required to generate fresh invoice .
(date of fresh invoice & credit not must same of wrongly issued invoice)

U may b received an intimation from assessing officer,then cash deposits in cash Register of ur gstin portel ,the difference rate may sett off through DRC 03 .