Open Quantity field in the Delivery Document (VL02N) doesn't get updated

Hi Experts,

The open quantity of the delivery document doesn't get reduced as the
stocks are being picked and delivered against the sales order.

Ideally the open order quantity should get reduced subsequent to any
delivery posted against the delivery document. But it doesn't happen in
our system.

Transaction - VL02N

I guess there might be something wrong in the copy control customizing in the delivery document.

Can someone please tell me where to find this customisation or on how to make the open order quantity to get updated when the stocks gets picked?

Thanks in advance.

Regards,

Randi