Originally Posted by
serfty
...Often the agent will simply make the change as a re-validation...easier for for agent to simply re-validate...
This assumes that a revalidation is possible and reasonable. Some airlines (such as AA) never revalidate (possibly because they use Sabre which I've heard does not support revalidation). Some travel agents tell me that they are prohibited from revalidating an RTW fare, even after travel has started. Even when revalidation is possible, it may not be wise on an RTW because of the mix of airline systems. I'm told that if an Amadeus airline revalidates, the Sabre airlines may not see it and hence would see the ticket as not matching the reservation and could cancel space.