I am in USA and my H1B visa with current employer A is expiring this month i.e. Jul 2018. Extension request is still in review which they should be filing soon. I have an offer from another employer B. When should I ask the employer B for visa transfer? 1. Is it after employer A files my request? In this case, should the extension be in premium mode or non premium? 2. Or can new employer B files my transfer irrespective of extension request filed by employer A?