If previous employer continues GC... when should I join ?

[pani321]

If pervious employer sponsors GC.... when should
we join the previous employer ?
Is it just after I-485 approval ?
Is it just after getting EAD ?
Is it OK to join any time after getting 485 approval ?

Dis anybody come across this case ?
Please let me know.

Thanks,

 

[jaxen]

Required to join JUST after I485 approval.
Expected to join after a EAD approval, but not required.
If AC21 is not exercised....