images Did you miss him? makeup good morning quotes inbillu05-27 12:52 PMbecause i was getting conflicting opinions, i consulted an immigration attorney from a big law firm. here is what he says: You can start working as soon the new company receives the h1b receipt notice.AC21 portability can be applied to H4 to H1 as well. Link to AC21 guide: http : // USCIS Home Page (http://www.uscis.gov)