更正：I-104 以及 I-485都pending半年可以换工作

法律条文叫做 21st century act (AC21)。 见下面。不过这个是拿到绿卡之前可以换工作，不一定适合拿到之后马上换？

Section 106(c): Change of Employment Permitted in Cases of Lengthy Adjustment Adjudication

If an applicant for adjustment wishes to take a new job in the same or similar occupational classification at the job that was the basis of his or her employment-based I-140 AND the I-485 has been pending 180 days or more, the new employer may be substituted into the existing I-485 application without disrupting the application at all.

This is accomplished very easily - NO new petition and no new fees.

Step 1: The applicant notifies INS of the change in intent by letter.

Step 2: The Service should then make a request for a letter of employment from the new employer.