enum constants

Hi

I'm in need of a little help using enum constants.

In my VI i'm using a case structure that is controlled by an enum constant. In my case named "85-94" i need a third option, which is change the case to "0-20 (Start)", if the slide goes below 21.

I've tried several thing, but i cannot figure out how i can do it. 

Anyone got a hint?

Thanks