I have one flight left for 2011, but realized that after this flight, I'm now 500 miles short of E status for 2012.

Can I change one leg of my flight to Executive from T+ to get the 150% status miles? My flight is RT YYZ-LAX, so I figure one leg will make status.

I'm a bit confused as to whether or not I can do so, and if I can, will doing so in advance cost me more than if I do it at the airport as standby?