My visa is B1/B2, but at the entrance I didn't show any paper together with my visa so I was admitted under B2 status. The https://i94.cbp.dhs.gov/I94/request.html clearly says I am B2 and not B1.
The problem is that my last medical clerkship, which starts in *October 7th*, requires me to have B1 status (its at the NIH).
Can I leave the US to Canada (I'm in Boston), re-enter one or two days later (or the same day, or not even actually enter Canada), properly showing the US immigration officer my paper from the NIH, and this way get a new *admittance status*? If not, can this be done if I fly a country that is not Canada or Mexico? (idea from this website: http://iss.washington.edu/procedures/change-status )
Remember, I don't need a new visa, I only need a new admittance status.