DCGR reversal

Hi Gurus,

PO was created for the 800 CS quantity..GR has made first for 800 and DCGR also got created.

When GR has reversed, the DCGR also revresed, but IN PO history tab..for DCGR details.. quantity is showing zero but amount is showing still... value was not reveresd at the time of Gr reversal...

Please suggest how i can rectify this now

regards

subbu