Hello Yogesh
As you mentioned you have sales orders which are partially confirmed meaning you have Schedule line(SL)#1 with confirmed qty and SL#2 which has some open(unconfirmed) qty. You do not want to lose the confirmation of SL#1 after running the BOP or in other words, you do want to reschedule SL#1 after running the BOP.
In this case, one oblivious solution would be running the delivery creation job just before the BOP job, if SL#1 is confirmed against Stock, then delivery will get created for the same(provided it is into the date range for delivery creation). Now when you will run BOP next time, it will only process an open qty which is available in SL#2. SL#1 for which delivery is already created will not get picked during BOP.
But if SL#1 is confirmed against future receipts(like PO or ASN) then even after running Delivery Creation(which usually considers only Physical stock), it will not create delivery for SL#1. However in this case, if BOP is run it should help improve Delivery date or improve Confirmed Qty requires having correct sorting criteria. Usually this kind of rescheduling is acceptable to the business. If it is not acceptable to business, then it would be interesting to know the business rationale and real requirement for the same.
Please let me know if above explanation helps.
Thank you
Satish Waghmare