How to correct quantity on inventory transaction posted against PO invoice

Hi all,

I have a case where quantity on inventory transaction was updated wrongly.User posted PO invoice with Qty 1 CTN(CTN is unit) On Item master we have defined inventory unit as PKT If i check inventory transaction on item master then there it is showing wrong quantity.

ON PO line Qty - 1CTN

Inventory transaction Qty - 20000 

Unit conversion shows 1CTN = 200 PKT

Below are the screen shots for same.Kindly help to know how can i correct this quantity on inventory transaction.

Thanks,

Shri