My votes: New/Amend Order

Not all items are delivered to the to the default delivery address so you should be able to amend the delivery address for direct deliveries from the supplier on free text items

In summary: 1) You cannot alter By default supply to on an existing purchase order 2) You cannot enter or amend a delivery address for a whole purchase order 3) You can only specify a delivery address on each line item by ticking the box labelled ...