CHANGING EMPLOYER DURING GREEN CARD PROCESSING
You can always change employers.
However, by doing so prior to reaching a certain stage in your Green Card processing, you may jeopardize the application process and thus be forced to start again from the beginning.
Under AC21, in order to be able to change employers and be able to continue with Green Card processing, there are three (3) main criteria.
USCIS has not provided regulations on this issue, but it is generally felt that "same or similar" occupational classification ties to the US Dept of Labor's job classification listed on the labor certification application, which should also correspond to a job code listed on the I-140 petition. Sometimes this analysis is very straightforward; but it can often be complicated. One recurring issue relates to a technical employee who is now eligible for a managerial position. The managerial position could arguably be in a different job classification and may not qualify under AC21 portability
Also, be sure to:
File AC21 letter with USCIS to update them concerning change of employers
USCIS recommends that the individual update the USCIS of a change of employers. Normally the update would include a letter from the individual (or preferably the new employer) attesting to the new position, with a discussion of the new job and how it is within the same or similar occupation as the prior labor certification and I-140.
File Form AR-11 if you move
Contact an attorney for guidance in dealing with issues relating to change of employment.
If, as a result of new employment, the foreign national moves to a new home address, then the foreign national must update USCIS of his or her new address, using Form AR-11, found at www.uscis.gov. Be sure to update USCIS for all family members with I-485 applications pending, as USCIS does mail notices directly to home addresses in the I-485 process, including eventually the I-551 permanent resident card. IMPORTANTLY, USCIS has a special (and somewhat annoying) arrangement with the US Post Office so that even if a foreign national tells the post office that he has moved, the Postal Service is PROHIBITED from forwarding mail sent by USCIS. This creates a lot of problems for people who do not know this rule.