Currently I am on H1B (extended till 2015) , I plan to resign from my employer and do a COS to H4. My questions are 1. How early do I need to file COS, before I resign? 2. Am I on H4 once I file COS online, or is it only once I receive the acknowledgment receipt? 3. How much time will it take to get the receipt. 4. If I file COS , resign and then receive the receipt post my resignation will I not be out of status for those many days? 5. Will my H1B be revoked once I do a COS?