To change the method of shipping on an invoice which has not yet been sent to the supplier, you will have to go to the invoice. At the top of the invoice, you should click on the link titled ‘Edit Invoice Header’. While in there, you will have to scroll down to the ‘Shipping Box’. Next to that box you will see a code, for example UPG (which stands for ground shipping). You can leave it as is or change the code to the desired shipping method. Once you have made the appropriate changes, scroll back up and click on the button ‘Save w/Freight Update’ and that should make the changes to the method of shipping for that invoice.