Yeah, the UA1/2 cancellation is kinda surprising IMO. With all the PW 772s coming back online, there's been quite a bit of slack in the widebody fleet lately, so it's odd/annoying that UA couldn't/wouldn't shift some flying around to get a 789 out to SIN tonight or even tomorrow morning. Of the aircraft in the UA fleet, only the 789 can make it on SFO-SIN, but perhaps a 789 previously assigned to a rotation of SFO-LHR and beyond could have been swapped with a 772, etc.