"Color Table Generator.vi" in the "Create IntGraph ColorTable.vi" example in plain old LV. I use a (very modified) version of this to adjust the color schemes on intensity graphs, since the Z scale adjuster is one of the more frustrating widgets in LabVIEW. Frustrating, obtuse, very non-intuitive, and except for the simplest of things, often unusable.
But I digress... The example shows you how to move a point around on the graph. Or rather, you move a free-dragging cursor away from the apex point in the middle of the plot, and the slope of the plot changes from that middle point to the static points on either side to make that new point the apex.