Change PTO Model BOM after item is used od Sales Order

Hi to all. Is there a way to reflect changes in the PTO Model BOM on a Sales Order, but for the Sales Order line created before BOM is additionaly modified?
For example, customer created PTO Model BOM with few included items, and after that created Sales Order using PTO Model.
In that point of time, PTO Model BOM is not completed, but customer wants to add items to Sales Order in order to be able to reserve goods on stock.
After some time, additional items are added to BOM, and also those items should appear on the same Sales Order.