Converting Selected Quotation lines to Sale order

I’d like to clarify our requirement regarding converting quotations to sales orders:

Initial Process:

We generate a quotation with 10 line items.

Out of these, only 4 lines are confirmed by the client.

We need the ability to create a sales order with just these 4 confirmed lines (selectively).

Subsequent Addition:

Later, if the client confirms an additional line item from the original quotation, we’d like to either:

Add it to the existing sales order (if possible), or

Create a new sales order for the additional line.