ITC WRONGLY AVAILED IN GSTR 3B

ITC wrongly availed in GSTR 3B, now how to rectify it in GSTR 9.
In GSTR 3B IGST credit wrongly taken, but actually there is no IGST credit. how to rectify it in GSTR 9. Because in table 9 of GSTR 9,liability is automatically set off against the wrongly availed IGST.
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