先謝謝老師的回複！
那麽我再次請教老師：I-140批準 180天內或者之後更換雇主所產生的變化有哪些本質的不同呢？
-A little. If the employer withdraw the approved I-140 (within 180 days), you cannot use it to extend your H-1 beyond the 6-year limit and other benefit such as spouse cannot use it to apply for H-4 EAD. But you still can keep the priority date for your new I-140.
