Originally Posted by percysmith

If there is a confirmed delay NRT desk may reroute you. They've done it for me https://www.flyertalk.com/forum/36255461-post7.html

(Come to think of it this example is extremely apt - in May 2024 my wife's family and I were on CX451-CX451 on two separate tickets (wife's dad wanted TW and wife and her mum wanted JP - no redemptions with partners available, so the only way I can think of to take them all on miles was HKG-TPE-HKG and TPE-NRT-TPE). CX NRT checked us through and gave us two CX451 boarding passes and two lounge invites each, then called me back to desk because of bad weather over Taipei and exchanged our two boarding passes for direct CX521. Our flight diverted west of track all the way to Shanghai on the way back)