Hi
I have a valid EAD with my previous employer, till July 2010 and cannot file for H1 as i been working on EAD for last 4 years..never filed for H1 extension after 6 years on H1.
-------------------If you have valid EAD that is good. FYI the EAD is not based on employer A or B. EAD ,AP are based on your pending I-485 and I-485 belongs to you not to employer A or B.
can my company cancel I -140?
----------------- How do I know if your employer want to revoke your I-140? by law employer can any time revoke the I-140.
do i need to file it again from new company to be on safe side, is there any web link explaining how all this I 140 or AC21 work
-------------if I-140 approved and I-485 pending more than 180 days then you are eligible for AC21. you can search for AC21 MEMO or read the thread related to AC21.