Portability
Since the American Competitiveness in the 21st Century Act of 2000 (AC21) was initiated, foreign national employees in the U.S. on H-1B visas and I-140 employer petitions need not wait for the approval of new USCIS paperwork to switch employers and re-begin working. Instead they can return to work as soon as the new employer files its paperwork. Of great advantage is that the new employer does not need to process a new Labor certification. Legal opinions are divided on whether the portability can go from an exempt employer without a quota, like a university to a quota based employer. We feel portability can still occur if all the requirements of it are met. A viable alternative would be a new employer submittal with a premium processing service.
Key to a legal transition is that the new job is the same or similar occupation classification and the new petition is a non-frivolous petition with a legitimate employer. It need not be in the same geographic location of the U.S. During portability, travel overseas is permitted, but the employee should carry, with it, proof that the second employer filed the requisite petition.
H-1B Portability
The old method for H-1B visa holders was to enter the U.S. and work for their employer. If they became disgruntled of sought green pastures the new employer had to re-file and the H-1B visa holder could not switch employers until the new visa was approved. Often a very lengthy process. AC21 has changed that. Since, technically the old employer must pay the employee until the H-1B is withdrawn, normally the former employer will immediately send in a Revocation Notice once learning that the employee is leaving for new employment.
Pending I-485 Portability Based Upon Employment Related I-140 Petitions
Where employment was based upon an employer filed I-140 portability can occur provided the employee only leaves its sponsoring employer 180 calendar days after the filing of the I-485 and further provided it has been approved. Leaving before that time will bar changing employers. Naturally, the new job must be in a same or similar occupation classification. Consequently the permanent residency processing will continue.