回复：回复：回复：回复：回复：回复：回复：回复：回复：回复：回复：请教关于EB1b和NIW的一个问题，可能有点复杂， 多谢各位大

Just regarding to your answer, is that true after I-140 get approved for 180 days, it can not be withdrawed?

-Your employer can withdraw the I-140 anytime, but it will not affect your I-485 if your I-485 is pending for more than 180 days. So, it does not matter to you in that case. The problem is that if your employer withdraw the I-140 before your I-485 is pending > 180 days, your I-485 will be denied and you will lose the I-485 filing fee (no other loss).

or that's just my misunderstanding? 

Again, thank you very much!