I’m back, wondering if anyone knows what happens if a connecting flight gets canceled at NRT.

We’re flying YVR-NRT-SIN, AC then NH, all on one ticket. Looks like 801 (NRT-SIN) was canceled yesterday - it doesn’t show a reason, and I’m not sure how far in advance. But assuming one is already enroute to NRT, what happens?

i assume they will try to rebook as many connections as possible onto SQ flight, or maybe on connections via NH/TG via BKK, or maybe other reasonable connection options, but also suspect without flexibility to do it beyond same evening (or using HND flights either), it might be hard capacity-wise for an entire canceled flight. Sure I’m worried over nothing, but trying to plan in case some ‘creativity’ is necessary.