Unable to Reverse PGI and remove assignment of HU

Hi Gurus,

I am trying to reverse the PGI in VL09 and while doing so, I get an error message " Post the HUs for goods receipt so that they can be transfer posted" ( Message no. HUFUNCTIONS254).

While I go in delivery in change mode and try to delete this HU assignment, I am unable to do so. When i go to HU tab the change mode disappears and HU is in Display mode.

Please help to reverse the PGI.

Thanks in advance,

Shash