ur answers r horribly misleading

1) she does NOT have to give up the I-94 card, especially flights to Canada;

2)if she has the original white I-94, the original visa (F1 or whatever) and I-797A with valid I-94 attached below, of cuz she can get back under "30-day" policy.

the side-effect of using AP could be really severe;

3) my friend just did her landing. when she came back, she told US officer exactly what she had done.