BostonBoy.....I know what it is like trying to track a girlfriend down. I know DL doesn't give out info on other passengers records but what I do is tell them to pull up flight XXX for (whatever date) last name of XXXX (all of this would be the original flight record that she held). Then I ask if she was able to take an earlier flight or "what happened with the weather? Did DL put her on another flight?" or "she said there were maintenance problems. What did DL do about that?" They will usually fill me in with where she is.
Chris Moss