Hi @Britt, It sounds like you are using the conditional formatting in the UI. Currently, this feature can only interpret the measures it's being applied to, and can't reference a "call-out-date" or another field.
However, this can be accomplished by using conditional formatting with the html parameter. This gives more granular control over which cells to apply conditional formatting rules. Check out this conditional formatting with
html article to see some examples of how to do this.
Thanks for the question!