I'm a physician who has just completed residency training on H1b. Since my new job begins 2 months after completion, I had to change to H4 under my wife's H1. Now, I'm filing for H1 again, by a US employer(university). My wife and I plan to travel to Canada for a conference in October.

1. To start working, can I do so right after getting my new H1b I-797, or do I need to get my visa stamped by going out of the country.

2. Though it is recommended to go to home country for change of status stamping, as my Canada trip is important, and as I have already been on an H1, with US training, and having a US employer, would it be reasonable to go to Canada to get my new H1 stamped.

3. Is there a clause where one can return from Canada within a month without going for stamping?