Converting Orders to Leasing/Financing Companies

Our business works in an industry where our Sales Orders can be converted to leasing or financing companies after an invoice has been generated. Where we run into an issue is if that Invoice was generated in a prior and closed period. Our current business process sees us as having to RMA the SO, Credit Memo the Invoice and build a new order where the customer is the leasing company. This causes us a ton of back-end work that feels unnecessary. What does everyone else do in this case? Do you just update the Bill To address to the leasing