File EB2 to EB3 downgrade, leave employer with i140 pending?

My current company is not doing well and its under bankruptcy protection. I have EB2 with priority date of Mar 2010 with same employer. Employer ready to support EB3 downgrade option next month as Filing date is current. I never applied EAD before.

I have following question.

I would downgrade to EB3 and concurrently file I-485/EAD etc. Nowadays , I-140 regular approval is taking more than 6 month for approval.

What would happen if I leave the current employer after 180 days of my I-485 receipt notice but still underlaying EB3 I-140 is pending. If I do AC21 to new employer but still I-140 pending, what are all the issues needs to be considered? If its 180 days, is it automatically approvable when I do AC21 if its filed with proper documentation?

If you leave while EB3 i140 is pending, the chances are high for RFE and then rejection as you would not be working for that employer.

Thanks. If i140/i485 pending for more than 180 days, can I do anything for I140 RFE or fate is decided based on i140 only?
ie Does USCIS consider my case if I do AC21 after 180 days but I140 is pending ?

AC21 rule comes into picture only if i140 is approved.
If you receive RFE on i140, how will you respond to it if you are not working for that employer at that time?

Also, the chances are high that your employer would itself withdraw the pending i140 when you leave.

If your i140 is ultimately approved, you can still use AC21 portability. But, it depends on on your employer and if they file for withdrawal before it’s approval or not.

Thanks Anil. Let’s say employer does not revoke my i-140 petition as I would leave with good term with mutual understanding.

If i-140 is pending for more than 180 days, in that case does USCIS would do any weightage for my AC21 with new employer’s JobDetails/Supplement J ? ie Can I do something to any I-140 REF ?

USCIS may or may not give weightage to new employer.
We can’t really say for sure.

Usually, they do.