My H1B has been changed from university to nonprofit company recently. Currently I'm still in the university and waiting for the leagl date to start my new position. The company lawyer sent my application to the USCIS last week. The company told me that I could start the new position at the second day after submitting the application. I don't think so. My question is what's the earliest legal date to start the new position, after receiving the reciept or the approval notice? I need to estimate the end date of my current employment. Thanks