I-140 and H1B Portability Under Act 21

Generally, an lien in H1B status may work for up to six years. Before obtaining another round of H1B status, the alien must return to his home country for one year. Yet Act 21 gives some H1B holders opportunities to extend H1b status beyond 6-year limit. There are two common scenarios:  

1) If the H-1B holder has filed either a Labor Certification application

or an I-140 petition 365 days before reaching the six-year limitation AND the LC or I-140 has not been denied, the H-1B visa holder may extend his or her status one year at a time beyond the six-year limitation.  There is no upper limit on total years in H-1B extension under such a circumstance as long as the immigration process is still ongoing; 

2)  If an H-1B visa holder has an approved I-140 petition AND the immigrant visa number is not available to him/her the H-1B visa holder may extend his/her status in three-year intervals beyond the 6-year limit. There is no 365-day requirement for this circumstance.

On the other note, H-1B Not Limited to the Permanent Residency Petitioner Employer. That is to say, H1B holder can receive a new H1B visa as long as the sponsor is willing to continue to sponsor the immigration petition. However, he/she needs to come back to work for his/her PERM sponsoring employer either during I-485 or after his/her green card is approved.

I-140 Portability under Act 21. 

Where the labor certification is approved, the I-140 petition is approved and the I-485 application has been pending for 180 days or longer, there is nothing that the previous employer can do to stop the new employer from using the underlying labor certification and I-140 approvals.  At this point, the foreign worker retains his right to the labor certification and I-140 petition and the new employer need not file either.  The new employer need only explain how the new job is "the same, or substantially similar" to the job described in the labor certification application.  The new job does not need to be in the same city, the same state, or at the same salary as the job listed in the underlying labor certification so long as the new job is the same, or substantially similar to the old job.  

Before the I-485 application to adjust status has been pending for 180 days, the earlier employer may withdraw the approved I-140 petition.  If the employer does so, the employee may not use the I-140 petition as the basis for an I-485 application and if the employee has a pending I-485 application, USCIS will almost certainly deny it.