Order Products refer to the product that are on an Order.
Navigate to "Orders" > "Orders"
Select the order that has the product that will be changed
See: Creating New Orders
Click the [✎] button next to the product that needs to be changed
Change the prices that need to be altered
After making your changes, click [✓Update]
Note: This will only affect the product that is ran off of this order and will not affect your Products & Pricing