If the goods have already been shipped, I think you'll need to ask for a correction from the customs agent who handles the goods after they've crossed into the country.
If you are an Alina Global seller, before the shipment is complete, in the mid-shipping state, you can contact Substitute Buyer B to change the customs code of Original Seller A and request a corrective dispatch. However, it must be checked again that the actual action has been taken because each seller reads the requested call back and forth.