update a CODE FOR ORDERING REASON in PO

Hi all,

I need to do a mass update of the purchase orders with the non compliant code u201Cu201D1u201Du201D on the retail tab in the reason for ordering field.

They should be providing a single template with the following 3 fields:

PO NUMBER

PO ITEM NUMBER

CODE FOR ORDERING REASON

I have tried to do it using tx code MEMASSPO but I could not find the field BSGRU (reason for ord.)

any idea how can I do this mass update?