I am currently on H1B , expiring in July 2013. I plan to go on H4 from May 2013. My H1 extension will be submitted soon. If I go in H4 will my H1 work permit also get cancelled ? Or after sometime will I be able to join back on same permit assuming the H1 extension goes through and is valid then. Also if I do COS to H4 while extension of H1 is in process will that request get cancelled or will it go through? I am not resigning from my employer and plan to go in H4 by taking unpaid leave.