I for one think the credit DL's rebooking system seems to get is overblown. My experience is that it works for simple itins, but anything somewhat more involved it never works. Kinda like delta.com when booking.
Example:
Missed ATL-IAH flight, rebooks onto next available flight an hour later. No problem.
Missed double connection? Ha! Had me walking from MSP-ATL and arriving home 26 hours late despite many other options which were available. Spent the entire flight into MSP trying to rebook on dl.com to no avail. Fixed by SC agent in 5 minutes.