Create only 'On-Account' from Return Sales Order

Summary:

We are using Order Management to create Sales Orders. These are ultimately billed and create an AR Invoice.

If the customer would like to return an item a return is done against the original sales order. This is done by querying this order via Order Management and clicking the 'Return' button.

When this return order is billed it creates a Credit Memo in AR. This Credit Memo is automatically applied to the original invoice if it has not been paid.

Instead of this we would like the Credit to be created 'On-Account' only and not linked to the original Invoice.