I am student doing my Masters. I intend starting my OPT from October 1, 2007. An employer has agreed to file H1B for me after April 1, 2008. I guess my H1B Visa will be approved some time in June/July 2008. I want to know when will my status be changed from F1 to H1B. Will it be effective from the data of approval of H1B or will be effective from October 1, 2008. I guess this will be stated in the new I-94 card. What date will be mentioned in the I-94 card ?