Originally Posted by
cre95
I would buy the BOS-ORD and ORD-LGA legs now. If you are concerned about these being canceled due to Delta noticing you have alternate flights on the same dates, skip adding your FF number on these legs for now. Plan on updating the record with your number after you’ve had a chance to cancel the legs in your existing ticket that you won’t be taking.
Then OP would at best get a gate/battlefield upgrade on the new segments. I'm not sure keeping the FF number off the ticket matters much for conflicting reservations.