The only way to completely convert from one kind of grass to another is to kill and start over. I tired to overseed a KBG/tall fescue lawn with native grasses, figuring that over time, the KBG and tall fescue would die because they need so much more care than the natives. I had to overseed a number of times and, although the lawn now has native grass throughout, it still has a fair amount of KBG and tall fescue. If that's the case with grasses that have such differing needs in a desert environment, I doubt if you could succeed with grasses that have similar needs. You could probably favor the tall fescue by fertilizing and watering more, since fine fescue needs less of both, but since tall fescue doesn't spread much, you'll probably need to overseed regularly. And even then, you're likely to end up with the tall fescue dominating, not completely replacing the fine fescue.

Also in Chesterfield - Those pics you posted are exactly what my lawn looked like last year. I too have lawn service (VA Green) and spend TONS of time and effort. So when it was all perfect one minute then that, i was upset. Turned out to be fungal. Virginia Green upsold me on the "Estate" package that treats fungus. Two weeks later, the brown areas were gone and it was back to perfect. Now this year since i have that higher package, I dont have to worry about it coming back. And with 2 acres of just grass ... It looks great! The point of this post was to recommend VA Green over True Green which i've seen terrible things from here. Also to sucker you in to subscribing to their fungal package like me so I'm not the only one ha. The below pic was covered in brown last summer, just everywhere. Now its this after just 2 fungal treatments.

Its Tall fescue, and it would actually make a nice lawn if it was re-seeded with more tttf..... Its kind of "hit and miss" with seed from big box stores. Stay away from Scotts, Vigoro, Pennington and Lowe's brand -(Sta-green) Most products by Barenbrug are pretty good - including their tttf blend- 'Water Saver'........which is available at some retail outlets. Barenbrug does sell some cheap , common type grasses, but its obvious and out front. The other brands mentioned - hide sub par types in their blends , and you can't tell until the lawn is established , and you start noticing weedy off type grasses in your lawn.

Even bluegrass turns white and scared. While I haven't specifically tested it on TTTF, it's...er...accidentally drifted onto some weeds in my neighbors' lawns that happen to include TTTF. You know, by accident. And yes, TTTF does turn white. In October in the Northern hemisphere, I don't think it'd have time to turn back before winter and it'd maintain that color through the winter, or until dormancy, if yours does.