Originally Posted by
El Boocho
This is not scientific, but in my experience tickets that are simple, have never been reissued or changed and are all Delta can be sometimes be dealt with online. Any ticket with complications requires requires an agent. For me, as an example, if an upgrade has been processed online changes dont work.
I have had a similar experience after a schedule change (with a revenue ticket). Booked a trip to HND in May and initially the system would allow me to make changes using Modify Flight option and quoted fare differences online. However, after a schedule change impacted the itin, it now returns an error (#600104R) if I attempt to make changes and says it can't be changed online and must be done by an agent.