Xiaobaitu help: I-94 still valid? cth1632006-04-13 05:47:18

My wife has not turned in white original I-94 (valid till July 13, 06) after she filed F1 petition online. Is this I-94 still valid?
Can she go to Canada and use this I-94 to come back to U.S.? I understand that her F1 petition will be void since she leaves U.S. for a while, and she
has to cancel it. Right?

Thanks very much,

Yes,she's pending case will be revoked if she leave USA