回复：回复：回复：温哥华签证问题

If you still have a valid H4 visa with unused entry(entries), I believe you can come back to US no matter whether your new visa is issued or rejected.
If you only have a valid I94, I heard that when you apply for the visa, your I94 will be taken away by the visa officer. I don't know if this is true.
I got my H1 visa last September in Vancouver. At that time I was working in Canada. It took about one month to schedule the visa interview.
Good Luck!