Filing for I485 - Change of employer

[Vijay_PDX]

I am on EB2 with priority date OCT 2014. I have accepted a new position with a different company a month ago and working on paperwork for my H-1B transfer. However, my current employer now is willing to apply for EB2-to-EB3 downgrade plus I-485 simultaneously. I am confused if I have to move to new job. 

Based on timelines of my current employer legal team, it takes atleast 2 years from the time they apply for I-485 to interview & final decision. I am not sure how much additional time it takes to process I-140 on EB3. 

1) During this 2 year period of I-485 processing, if the dates are retrogressed, do I need to start a fresh paperwork and filing for I-485 based on EB2? 

2) When is safe period to change the employer after applying for I-485? 

3) Can I carry forward my existing EB2 priority date (OCT 2014) and file for EB3 through new company?

4) If I change employer & file for EB3 and if the dates are retrogressed during this process, do we need perm and I-140 freshly for EB2 filing via new employer? 

 

So much confusion 😞 any inputs are highly appreciated.

Thanks!!