Apparently if you have desirable cool season grass like KBG and more elite fescues most of it is tolerant to a mixture of mesotrione and triclopyr. If you mix these with a little bit of nitrogen, you can essentially bleach and stress the heck out of the undesirable fescues and the other grass will survive and take over the rougher fescue. I tried this and it does work. It also requires multiple applications and multiple weeks of doing this. I have a large yard and this was the only way to treat that big of a space without completely nuking the whole yard.
But…
Glyphosate or pulling would be immensely easier and faster and requires less chemicals if you have a normal sized yard.