During I-140/485 company change

[princerichy]

1) Do I change company during I-140 process?
A:yes
B:no
2)If I would have change company then to reapply for PERM(Labor) process with new company?
A:I have to reapply for labor certification with starting PERM process
B:I can update my data in old companies labor/I-140
3)Is it necessary to do within 6 years?
If i will not get labor within 6 years then any chance to extend H1 status?
4)If i will stay with old company and get approval for I-140 within 6 years then get 3/1 years extension.so during that extension time do change company?
A:yes
B:no
5)During that extension period,up to what time I have to wait for apply I-485?

please advise me...