Originally Posted by
link2
I remember one of the AA agents telling me explicitly that the flight I wanted to change to was no longer offered on RTWs fares but obviously they could have been mistaken.
AA RTW agents have told me the same, that there is a type of fare limitation.
ernestnywang has said there isn't such a mechanism, at least as far as he can tell (and has provided information to back that up), just the point of origin one.