There is no way to do this in OOTP, you would use the park factors to simulate that and
OOTP Park Gen, a fan-made online tool for making stadium dimensions will do this for you, but you can't do it in OOTP natively.
I have noticed that in the latest versions, the game will adjust the park factors when you pick the city (via the weather tab in the stadium area) and so that might be what it means w/r/t altitude adjustments, but you can't do this manually.