copying one product with its valuation to another

Dear Team,

i am using SAP BYD product in our company

I want to know whether we can copy one product balance qty & its valuation to other product code.

for example

product code       QTY   Value

ABC                   1          100

XYZ                    0          0

transfer valuation & qty to XYZ product

ABC                  0          0

XYZ                   1          100

Is due to we have many product which can be use as alternate code, but once sales order submitted, we can not change product code (because it is confirmed in customer purchase order also)

Please suggest if any process flow in SAP BYD.

Regards

Vishal Kambare

+91 986 725 4565