I know that with a valid I-94, I can travel to Canada and return without a visa stamp within 30 days. However, my H1-b was just renewed, and I have a new I-94 that came with the H1-b. My visa stamp has already expired. Would it be sufficient enough to allow me to come back to just show the new I-94 with the H1-b? Or would I need to get a visa stamp? Has anyone have the same situation happen? Thanks.