Traveling on a paid *A CRTW with a UA flight from ORD-NRT followed by an ANA flight from NRT-BKK and pre-assigned 2G.
Although 4A available ANA says can ONLY be re-assigned by United.
United says 4A not coded "Star" (I assume *A) so they cannot re-assign.
I have no idea what coded "Star" seating means - do you?