Should i Withdraw my I-765 Petition

Hi,

I have applied for OPT Extension on April 1st 2016 and got a RFE in May, As I was out of job and had difficulty addressing the New I-983 form. I have applied for COS from F1 to H4 and my H4 is approved. I checked the case status and it still shows the same receipt information(not even the RFE Information).

Now should i withdraw the Petition filed for OPT Extension or leave it without any action as my COS is already approved.

You can do either - leave it or withdraw it. Like you mention your COS is approved and so EAD extension is moot now. Personally, I would withdraw it.