Can I place a vessel sink over integral sink without cutting out existing sink. I
Depending on the sink it might be  possible. If you're talking about one of the larger vessel sinks that lay flat and would completely cover the sink opening then that may work. You'd probably need to cut the sink bowls out of the existing counter top so you can hook up the drain. The one problem you may have is if you will be able to mount the faucet behind the sink.