So I'm flying US34 on Sunday, 11/22/09. It's MEX-PHX-LAX, but it's considered a "through flight." So in order for me to be UG'd, seats in F must be available for BOTH legs; that is, I won't be UG'd for MEX-PHX if PHX-LAX is not available for UG, too (and vice versa).

Is there a way to have a res agent split the segments? BTW, I booked this on Orbitz, so maybe I need to contact Orbitz and not US?

Thanks.