Hoping the group can help me troubleshoot some issues my parents have encountered with Norwegian. Here's the backstory: They were flying BOS-CDG-BOS in Premium Economy on Norwegian in order to get to river cruise (they left 3 days buffer just in case). Booked with Chase Sapphire Reserve. Last night, Norwegian's 789 went tech and they cancelled the flight. I implored them to get documentation of everything for EU261 and travel insurance purposes. Not sure what transpired but Norwegian rebooked them JFK-CDG for the outbound, which is currently being operated by a Wamos A332 (someone please correct me if this is wrong). Norwegian didn't offer to get them to JFK from BOS, so parents booked a car and will plan to get reimbursed. Now, they're about 6 hours out and it looks like they're booked in economy. It looks like Wamos' A332 has business, so in my mind that's where they should be rebooked. Am I correct on this? Best way to convince Norwegian of this?

Add to this, in haste my dad booked a one-way Delta ticket BOS-CDG, and thought he could get Norwegian to pay for it ($2100 per person). I explained that would never happen and he runs the risk of having his return cancelled. If they choose to not fly Wamos (beyond the seating issue the online reviews are freaking them out...I know, I know), is there any way to get Norwegian to honor the back half of their RT ticket or will they be stuck in Paris?

To summarize: how do they get into Wamos' business or fly out on a different ticket without cancelling their return leg? Thanks for the help!