Originally Posted by PV_Premier

FYI, you can call UA and waitlist for other saver Y or F award routings to IAH. For instance, you can ask to be waitlisted in saver Y for up to two different nonstop flights, or you can request waitlist for both Saver Y and Saver F on the same flight. Check the consolidated award waitlisting thread in the UA forum for more info.

I would have booked the DFW flight, better chance of getting a W/A award on AS to DFW than IAH IMO, since you could also do SEA-PDX-DFW to get it.