Since you asked in this thread, I assume your flight is less than 96 hours away and if that's the case, you want to call ANA asap before asking here. ANA's 96 hour rule is flexible in such cases where the flight is cancelled or there's a covid related issue (positive or test result doesn't come before flight, etc.) And if flight cancellation occurs in the very last minute, ANA will let you take another carrier, another routing.