ITC claim wrong entry in GSTR 3B- doubt

Dear frds / experts,

For Sep'2018, I have wrongly taken the ITC value & filed GSTR 3B return wrongly. Just now I found the mistake. Now how to rectify this error in the 3B return? or how to resolve this problem??? plz treat very urgent and do needful at the earliest.

Thanks in advance.

-Maya.