根据移民局和国土安全局对21世纪提升美国国家竞争力法案（American Competitiveness in the 21st Century Act 俗称AC21）制定的职业移民最终规则，职业移民申请者在I-140批准后、绿卡批准前可以升迁、调动和换雇主，其I-140仍有效，但需要满足一些条件。这项规则在2017年1月17日生效。
职业移民类别中的 EB-1a Extraordinary Ability 、EB-2 National Interest Waiver 不需要雇主支持，也不需要申请劳工证（EAD），可以在其专业领域内随时换工作。
职业移民类别中的 EB-1b、EB-1c、EB-2（非 National Interest Waiver 类）、EB-3 需要雇主支持申请，这些申请者在换工作时需要满足一些条件，以保持他们I-140有效性。下面介绍的都是职业移民类别中的 EB-1b、EB-1c、EB-2、EB-3 申请者相关。
"Retention of employment-based immigrant visa petitions. To enhance job portability for certain workers with approved Form I-140 petitions in the EB-1, second preference (EB-2), and third preference (EB-3) categories, but who are unable to obtain LPR status due to immigrant visa backlogs, the final rule provides that Form I-140 petitions that have been approved for 180 days or more would no longer be subject to automatic revocation based solely on withdrawal by the petitioner or the termination of the petitioner's business. See final 8 CFR 205.1(a)(3)(iii)(C) and (D)."
"DHS is revising these provisions to clarify that a Form I-140 petition will remain approved if a request to withdraw it is received or the petitioner terminates its business 180 days or more after either the date of the petition's approval or the date of filing of an associated application for adjustment of status."
若原雇主在I-140批准后180天内撤回，那么新雇主需要为你提交新的 PERM 劳工证和新I-140，但原I-140的优先日期可保留，不需重新排期。
"Retention of priority dates. To enhance job portability for workers with approved Form I-140 petitions, the final rule explains the circumstances under which workers may retain priority dates and effectively transfer those dates to new and subsequently approved Form I-140 petitions. Priority date retention will generally be available as long as the approval of the initial Form I-140 petition was not revoked for fraud, willful misrepresentation of a material fact, the invalidation or revocation of a labor certification, or material error. This provision improves the ability of certain workers to accept promotions, change employers, or pursue other employment opportunities without fear of losing their place in line for immigrant visas. "
是否已提交 I-485 审理超过180天
如果申请者已经提交I-485调整身份180天以上，他可更换相同或类似岗位的新工作，不需要重新提交 I-140. 但申请者需要提交 I-485的补充表格J表（Form I-485 Supplement J）以及相关材料证明两个工作的相似性。
"If you have a pending Form I-485, Application to Register Permanent Residence or Adjust Status based on employment, you may be able to change the job or employer on which your Form I-140, Immigrant Petition for Alien Worker, is based as long as the new job offer is in the same or a similar occupational classification as the job offer for which the Form I-140 petition was filed. For you to change the offer of employment or employer, your Form I-485 must have been pending with USCIS for 180 days or more. You may request to 「port」 your job offer using the Form I-485, Supplement J, Confirmation of Bona Fide Job Offer or Request for Job Portability Under INA Section 204(j). Go to section 204(j) of the Immigration and Nationality Act (INA), which was enacted from section 106(c) of the American Competitiveness in the Twenty-first Century Act of 2000 (AC21), for more information.
The term 「port」 or 「porting」 means to change the offer of employment from one job or employer to another job or employer in a way that allows an applicant to remain eligible for a Green Card without having a new Form I-140, Immigrant Petition for Alien Worker filed for the applicant. "
- 及时提交 I-485 Supplement J。