Best practice for refunding a prepaid sales order

We have a customer who uses Shopify and imports those orders to Acumatica, along with the customer’s payment at the time the order is placed.

It is possible that an item becomes unavailable and the Sales Orders that have that item on them have to be partially refunded and that SO line canceled.

What best practices have you seen to:

1. Processes a partial refund on a prepaid sales order and sends that information back to Shopify.
2. Cancels the SO line for the affected item.

This would ideally be done in a bulk process. They could have several hundred sales orders with that item that need to be refunded.

Thanks for any help provided!