These fields are always directly editable when the Product is already in the order, as long as the order is not Exported:
- QTY value
- Price value (Apply a Discount to an Order)
- Add/Remove Product
- Description Line (See GIF below)
Remove and Re-add Product
For all other changes, you will need to:
- Remove the product from the order and Save the order
- Modify the Product attribute from your Products page
- Return to order, re-add the product back in (Add Products to an Order), and save the changes
The order can only display how your product looked when it was added to the order.
If you try to modify a Product that's still tied to other orders, you may see an error message. You will need to remove the product from all orders and then make the changes and re-add the product into the orders.