Handling Backorders with multiple warehouses

Currently with Netsuite we have a sales order that comes in that is assigned to back order to a warehouse that is closest to the customer. Sometimes though, the product will arrive in stock in another warehouse that the customer’s order is NOT assigned to that we need to MANUALLY go in and edit the order to change the warehouse. This process is very cumbersome and I’m looking for a more automated option for this. When changing the warehouse we also have to get our shipping rates again as well so that’s another step that is added on as well as changing the warehouse.