I'm on my 7th year of H1-B through Employer B. I have my I-140 approved and I-485 pending through Employer A. Employer B filed AC-21 and used the approved I-140 through Employer A for 3 year H1-B extension. It’s been over 3 years since my I485 was filed.

If I change to Employer C, say next year, can I get 3 years of H1-B extension again even if my approved I-140 was revoked by Employer A? Please note that I have filed for I-485 3 years ago.

If I stay with Employer B, how many times can I get 3 year H1-B extensions based on the approved I-140 and pending I-485 from Employer A? If Employer A chooses to revoke my approved I-140, can I still get 3 year H1-B extensions more than once through Employer B?