I'm trying to do this with a 1-stop SNA-BOS flights xORD.

The website will only show me middle seats which are available on both legs. I can see there are a fair number of "good" seats available on each leg but none that are the same.

Reservations said they couldn't do anything for me, so they transferred me to web-support. They are "checking" but it's not looking good.

Will it at least let me get different seats when I'm checking in? At the airport? Will I have to get off in ORD to ask for a different seat on the second leg?