An hour or 2 before scheduled boarding, equipment swap from 787-9 to 787-8, so reduction in J from 48 to 36, as well as another ~20 pax in coach. I was connecting from IAH, mayhem at the gate, and all the folks who got cut were sent to desks landside. GS line & Polaris lounge staff had no idea what was going on. THIS is when being GS makes a difference, I just kept reloading itinerary on my phone, got a preferred J seat. Also now know that 787-8 can reach SFO-SIN (ok we’re still 4 hours away, but I’m still hopeful )