No, unfortunately,under Portability Rules, unless your I-485 is pending for over 180 days, you may not port your approved I-140 to a new employer without loosibg your priority date, unless you have a good reason for going to a new company (other than just money or better work environment etc) and your current employer will continue with bona fide job offer (and you continue wanting to take the job adter you get a GC) on which the Immigrant Petition is based even though you do not work for them now. Said that, however, this scenario is rare and very hard to show as bona fide. The short answer is a NO. Please feel free to cobtact me at meltser@bmlaw.com