GSTR 3B wrongly filed

Wrongly filed GSTR 3B and paid GST in excess of amount. due.

 There is no option for correcting GSTR 3B once it is filed.

Whether I can prepare and file GSTR 3B by lessing of total taxable amount and GST  to adjust previous month's excess.

I opted quarterly filing of GSTR1 and not yet filed GSTR 1 for the above quarter. Please explain how I can file GSTR1 rectifying errors in GSTR3B

Thanks in Advance