To modify an order coming from Rakuten, modify the order as you would normally in Shopify.

  1. Select the order to be modified
  2. Click on "Restock" 
  3. Change your order appropriately
  4. Click on "Restock items"
  5. Wait for your order to be fulfillable 

The best way to access orders from Rakuten that are ready to be fulfilled is in the Rakuten sales channel main page in the "Orders" section.