PURCHASE RETURN SHOWB AS SALES IN GSTR-1

Initial period of GST ,purchase return to supplier,shown as outward supply and B2B in GSTR-1 return.
Further,supplier also issued credit note for sales return and entered in GSTR-1 and reflected in GSTR-2A of recipient.
What to do for purchase return.Whether amend the invoice with zero in taxable value,gst amount and invoice value.
Pl.suggest.