On H1b, -Eb2 to Eb3 downgrade

Hi Kumar,

One of my friend is on H1b Visa and have I-140 approved from previous employer A under Eb2 category. his priority date is Nov 2014. for OCt the filing date for India is Jan 1 2015 for EB3, so he is under this date. he doesnt have I140 approved from current employer C yet.
So , in order to best utilize this opportunity to get his greencard and EAD, what would be suggested course of action for him? Can his current employer C do something or he has to go back to previous employer A? Thank you for your help.