CP/I-485 question

[gchelp]

Is it necessary to apply for I-485 if You have just applied for CP?
I have just applied for CP and got the interview date also. Do i need to apply for I-485 before
I appear for CP interview?.

I heard that lots of employer prefer to have I-485 EAD/Advance Parole done so that in case any CP problem the candidate can back to US on Advance parole. Is that true??

Appreciate your immediate response.
gchelp

[immihelp]

If you are rejected CP, you can't come back on any visa or parole. Read about this on this web site in consular section.

You don't need to have I-485 applied if you have applied CP.

[slp888]

What is the procedure to switch from CP to AOS with pending I-140. I saw someone posting that send INS an amendment, if this is true, what info shall I included? Thanks