Feng Yu

I have a friend who came to US as F1, then changed to H1 with a new
I94, but no H1 stamp. I plans to go to Canada for a week. When coming
back from Canada, is a H1 stamp or just I94 card showing H1 status
needed? What other
documents are needed to carrry?

I have heared the re-entry rule changed this April, but only affects
to those who failed visa application in Canada, but I also heared
people got tougher check when enterting from Canada to USA on i94
rather than visa stamp...