view modification of field "total qty" on process order by CDHDR or CDPOS

Dear Gurus,

I u2018ve a process order where has been modified the field "total qty" (GAMNG).

I would know the value of that field beforE the modification.

I havenu2019t active modification log, but I thing that is however possible find out the old value of that fiel query the table CDHDR or CDPOS.

Will anyone explain how (which parameters use) run that tables?

Thanks in advance

Best Regards

Juan