Originally Posted by
fumje
From what I see looking at multi-city WAS-MIA-IAH, it's just giving a pair of one-way fares WAS-MIA + MIA-HOU — so how about just buy separate tickets? In IRROPS, they'll usually take pity on you. I've never been met with a hardline voiding of my second ticket.
The only downside of buying separate tickets is that it would be difficult to skip MIA and fly nonstop to Houston if the need arose. There isn't a great way to attach two coupons to one flight segment, so UA's auditing would likely get fouled up.
Now, skipping MIA doesn't appear to be on the table, so it's probably fine to book as separate tickets -- it really depends upon the OP's preference in the face of a long delay on the IAD-MIA flight.