Reverse COGI poting

Dear SAP Guru,

I have already completed delivery and PGI which month already closed. In that time there was a error in COGI. Later we change the date in current date and posted in COGI with quantity (unfortunately).

Now we want to reverse this COGI posting or is there other process to over come this problem that stock and financial entry can match.

Thanks for your advance co-operations.

Best Regards,

Shoyeb