They might as well just do it... Just tried to change to an earlier flight from SFO-LAX and they wanted $600-ish for the change; ($200 change ticket fee). rest is the fare difference. Hell, my entire RT trip (SFO-HKG) cost $657!!! I'll wait to see if I can get on an earlier flight day of departure. Not going to risk it by buying a OW to LAX on earlier flight and just show up for my connection to HKG.
Shame... As the cost for a OW for my date of travel is as follows: Basic Y cost - $140; Main cabin - $170; F - $274