My wife is a Canadian Citizen with H4 dependent visa. We live in US. She is going to graduate school. Her school offered F1. What is the easiest way to get her visa converted from H4 to F1? We are going out of country for two weeks, can the visa be converted at the port of entry in US or does she have to go to Canada? Which is the safest route for the F1 visa approval for Canadian Citizen? She has necessary F1 paper work from the school.