Currently, I have my own admin app that adds/removes items from existing, paid for orders. Here is the scenario I'm trying to resolve...
When adding an item to an order using Shopify's Admin API, an invoice is emailed to the customer, requesting for them to pay for the item. This works as intended. Now, if the customer no longer wants us to keep the item on the order, we have two different edge cases:
1. The customer paid for the item already. We use the Admin API to cancel and refund the item (which works successfully).
2. The customer does not want to pay for the item via the invoice and wants it removed from the order.
Currently, I cannot find a way to just remove the item from the order via Shopify Admin API without refunding the item. So, say the item is $30. Even if the customer hasn't paid for the item, a refund of $30 is issued when removing it from the order. The invoice isn't updated either! Here is a screenshot of what it looks like in Shopify Admin after trying to cancel the item:
To be clear, using the Edit button in Shopify Admin works correctly, updating the invoice and removing the item from the order. Any help would be greatly appreciated!