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I was working with Company A and they filed my H1B then Labor and then I-140. Recently company A was spurn off to company B and they have transferred all the H1 Bs to thier company. After that process company B have filed my H1b Extension. Now my question is that comapany B need to file any ammendment for my Labor and I-140 as they are filed earlier with company A. I am waiting on my priority date to be current for filling 485.

Few questions I have:

1. If I maintain my I-140 with company A and continue my GC processing and file 485 with company A will there be any problem as GC is for future employment
2. If an ammendment needs to be filed for my I-140 and if an RFE comes up and my priority date becomes current can I still file my 485.
3. Can i wait till my priority date becomes current and file an ammendment to I-140 while filling 485.
4. If my I-140 ammendment gets rejected for some reason then my whole GC process needs to be started from first. Please confirm.
5. can i go with I-140 ammendment premium process.
6. If I dont go with ammending I-140 with company A and can I get 3 more years of extension of H1b with company B.

please suggest me best way of addressing these issues.