My uncle, his wife, and their daughter came to the US on 1/22/06, via my mom's petition. So they've been here a little over a week. But their daughter needs to go back to China for school on 2/14/06 and the greencards haven't arrived at our residence yet. She has the alien number written on her Chinese passport, is that good enough, assuming that the greencard doesn't come before she leaves? Also, if its ok that she goes back to China and can come back without the greencard, what happens if there was an error on her greencard (ie fingerprint was blurry/messed up) and the US government requires her to go to an office for a re-print. But she won't be able to do so because she's in China. Thanks!