If you simply no show for your JFK-LAS flight, you should expect to have the remaining segments of your ticket cancelled and then retain whatever value they have under the ticket's fare rules. That may well be $0. Anything else is pure luck. Period.

Have you even called EK to determine what it will cost to reticket this without the JFK-LAS segment? You may find that the cost is minimal and that all of this silliness is for nothing. OTOH, maybe it is brutally expensive.

Unless you have a very high risk tolerance and are prepared to purchase new tickets, I would not expect "asking nicely" after a no show to work.