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I live in Canada with a German passport and a student visa. From a recent climbing trip to the US I still have this green I94-W form in my passport. I didn't surrender it on leaving the US back to Canada, because I expected to come back for another climbing trip relatively soon.
That trip got postponed a few times, and now the situation is that the I94-W would expire while I'm on the trip. That is, it would still be valid on entry, but not on exit.
Can I apply for a new I94-W at the border crossing, or can these Visa waivers not be extended back-to-back?