Hi,
Create a transaction variant for MB22 in SHD0 and make the quantity field as display only. In this case, user wont be able to change the reservation quantity in MB22 even if its not processed. So you may activate the variant for exact users only. If reservation quantity is to be changed, only specific users shall be allowed. Refer the doc: http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/a070bfbb-d34a-2d10-b092-ecbe0b0d4a4c?quicklink=index&…
Else, you may go for development using the BAdI already mentioned.
Regards,
AKPT
