Sir what to do with credit note received from my supplier, how can I reverse proportionate credit in respect such credit note in which I have already availed ITC against the original invoice
Credit Note from Suppliers means it's Purchase Return, Amount of GST has been mentioned in credit Note, you are required to Reverse the same from your ITC in GSTR 3B in "other ITC" column (i.e deduct that much ITC from your current ITC, like other Purchase Return)
Yes, deduct that from your current month ITC e.g Current month net ITC 40,000 credit note 6,000 than in other ITC column show net ITC of Rs. 34,000 in GSTR 3B