Getting this error Orderline has already dropped from warehouse, cannot be cancelled or edited

Summary:

Hi Team,

We have created a order with one item for 200quantity and it is having an substitute item.

Line is in awaiting shipping status. Business did the pick release and having only 100 quantity. So line got split and one went for staging and another for backorder.

Now order is having 1-1 is awaiting billing and 1-2 is in Backordered.

We tried to unschedule the call as we expect to get item get substitute and get processed.

But getting below error:

Getting this error Orderline has already dropped from warehouse, cannot be cancelled or edited

Can we have anyoption to subsitute the line item ?