Expect reissue to take several hours (2-3 hours is typical presuming you have around 30 segments). Most AA ticket counters cannot cope with it. LAX can (and does a good job). Ticket will have to be hand written and the tax calculation will exceed the computer limits so it also must be by hand. You can ask AA RTW desk where they recommend having it re-issued, also be sure that they have fully completed the re-routing and tax calculation before you go to the airport for the re-issue. Expect the taxes to be wrong by a few hundred dollars (not in your favour).