Airlines change fare policies quickly, however, so call airlines regularly. Airlines don t like this approach and they can assess you for the full fare if you re caught. Use two different airlines. The only catch is that you may not get frequent-flier miles and changing plans may be more restrictive. You can call directly or use a travel agent.
Some airlines have their own consolidators.
European Travel Network is a huge system of consolidators, discounters and bucket shops that can help with low-priced overseas trips. You can also try 1 Discount Travel Agency. If frequent-flier miles are important to you, choose a consolidator that gets paid by negotiating commissions with the airlines. On resale, consolidators retain only a fraction of that commission. They pass the rest of the commission on as a reduction in price.