This is why having an AC membership is very valuable even if you pay out of pocket for it. I look on my phone, find flights that look like they have available seats (I jot down several options). Go to the AC desk, they change my flights. I have a drink (or two) in the AC, board my new flight and off I go. With load factors expected at 90% this summer it's going to be hell from hell. Unless you're a CK you're probably on your own. If you do need to call do your homework.