I am scheduled to fly on UA947 IAD-LAX in NC Tomorrow Nov 27. I want to know if there could be a plane swap as I have noticed two things that could lead to it.

1. It went from NC0 to NC9 overnight
2. UA.com wont let me look at the seat map for any cabin.

Is there any way to try to find out if there was a swap. The original plane is a intl 777.

Thanks
Ben