I know it is not possible but posting this here maybe someone came across the same requirement. A client with salesforce interface into Odoo submitted quotes with hundres of line items. The Quote is processed, confirmed and invoiced in Odoo.

Now customer confirms a subset of line items, were client want to confirm this subset, which he then delivers and invoices.
A month or two down the line customer confirms a second subset of line items and client wants to confirm these line items for delivery.

Sounds impossible in Odoo and my first workaround i advised my client to submit subsets from salesforce.

any ideas are welcome