Take the example from Nissan Juke dashboard: There are 2 modes in the dashboard, the first mode is when the label shows "A/C" and in the other mode, it shows the label "Normal". I was wondering how the label changes on the same space and how it works. See below:
As IHaveNoIdeaWhatI'mDoing stated in the comments, the buttons themselves have small LCD or OLED screens that allow them to change depending on some set of predetermined conditions. i.e. when the a/c is on, the button displays 'normal', and pressing it turns the a/c off, and when the a/c is off the button displays 'a/c' and pressing it turns the a/c on.