I asked this question before, mems answered it, thanks mems.
I just want to know more about this.
If the I-94 white card I got when I first came US expired, but I got H1-B extension, INS issued a new I-797 (with a new I-94 on bottom of it), can I go to Canada and come back using this I-94 on I-797 form?
Did anybody have experence about this? Or have any web links about this? Thank you.