Thanks for the reply 6rugrats. Yes, I'm never thrilled about booking through third-party sites but unfortunately we tried to go cheap for this trip and are now paying the price. I've booked with Orbitz before and have always been notified in the past when there has been a schedule change, so I'm not sure why we didn't get notified this time. Ah well, too late for that now.

To reply to your questions, yes, this is all booked as one ticket on LAN, and Orbitz says they can't make any changes without going through LAN since they own the ticket. I've asked about the 8:55 PM flight but Orbitz says that the layover time is a hair under regulation for MIA so they can't do it. They said LAN might be able to, but even if they can I am slightly worried about getting through customs in time since, as you say, MIA can be a zoo.

Right now we're looking at just flying BOG-MIA on the 28th, staying overnight in MIA and taking the scheduled flight to RDU on the 29th. The problem is just that apparently only LAN can make any necessary changes to make this (or anything) happen, and no one can get through to LAN. The LAN agent I talked to today tried to tell me that the LAN travel agent desk was open 9-5 and taking calls, and there should be no reason why Orbitz couldn't get through to them. Five hours on hold seems to say otherwise.