I am using a Lumia 735 running Ver 8.1 Update 2 and when I make a 3 Way call (two other parties) and want to end only one of the calls, I can't find an option one call. I either have to end both calls by pressing "End Call", or keep both on the line. There is no "Flash" button either to toggle to one call or the other. Seems to be a very basic function, but doesn't exist.