How do you adjust your gas range for high altitudes?

I can tell you how it IS done, not how to do it. At high altitudes there's less air available for combustion because the atmospheric pressure is lower. To get the proper air/fuel ratio, they change the orifices the gas passes through to smaller ones, and they adjust the regulator to compensate for the smaller amount of gas being supplied to the flame. This is something a professional service technician needs to do for two reasons, both equally important. A four-burner range has five orifices, but they might use five different ones getting the size exactly right--meaning you need a set of every possible size, and that's really expensive. The other is you need experience in evaluating the flame to get it right. And the nice thing is, your gas company will do this for either free or a very low cost, because they know they'll get back the cost of the service call when you cook on the range.