As far as i know, RELEASE and NOC is the same. No objection certificate or release must be provided by your previous employer in order for you to get job from another company. If no NOC that means, your visa is not transferable to another sponsor and subject for cancellation, and you will be returning home to your country and wait for 2 years to lift your ban. My advise for you is ask and talk seriously with your boss (GM) or your company H.R officer to ask NOC or release... God Bless...