It looks like AC26/03Jul was initally delayed 18hrs, than cancelled, due to WXX/Thunderstorms in PVG (there aren't any further details available). It was replaced by AC2026 which left PVG at 1006/04Jul. AC2026 is estimated to arrive in YVR at 0649/04Jul where, I assume, he has been rebooked onto the first available AC YVR-SFO flight. I do not know if that is the case for sure, but that would be my guess.