I am working with Company A on H1. Company B has filied my H1 & it approved but now I am not able to join company B. I got offer from company C. Can I file my H1 with company C? CompanyB is not giving me copy of approved petition. I am having copy of I-797 C notice of action that they got at the time of application filed up with USCIS. Is there any way can I got the approval copy of employer B?