Approved I-140 by employer A , looking to move to employer B

[So_Kor]

Hi,

I have approved an I-140 from employer A and I am looking to move to employer B, can you please help me answer the following questions,

1. What happens if I move to employer B before 180 days of I-140 approval? and what does it mean if it’s revoked and it is the impact on my stay in US.
2. What happens if I move to employer B after 180 days of I-140 approval? and can it be revoked after 180 days of approval or can it be only withdrawn.
3. If employer B does H1B transfer and it’s approved based on my approved I-140 from employer A after I join employer B and once employer A withdraws or revokes my I-140 , does this impact my approved H1B petition with employer B?
4. Can it be revoked after 180 days of approval under any condition and what happens if it's revoked , is my priority date retained and can I use the I-140 for my further H1B extensions?

Thanks for your help.