Add a nonzero value item to a Shopify order

At this time, adding a non-zero value item to a Shopify order (post-purchase) is not possible.

This is because:

• Ochre currently permits only zero-value items to existing orders; and
• There is no mechanism to update a third-party retail (3PR) order once ingested. 

As Shopify does permit the action - and also has a mechanism to email an additional invoice to the customer - we plan to make one of the two routes available in the near future. 

Please consider whether creating a separate order can achieve the desired goal. Any new orders created on Shopify will be automatically ingested and can be processed as normal.