yes, firstly you need to revised your B2C sale by deducting portion of that B2B invoice , it will reduced your B2C sales , after that you can upload that b2b invoice
First you go to amend the detail of B2C Column up to amount which you entered wrongly B2B invoices in B2C Column then go to B2B Colum and entered the B2B invoice with original date of invoice(back dated invoice)
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