When you pick up your kalimba and play, it is usually in a particular key. The Alto usually comes in G major. The Bb Treble comes in Bb. The 17-Note African-tuned karimba comes in A (unless we retune it), and the 15-Note Karimba (ie, mbira nyunga nyunga) comes in F.
However, the same set of notes can be used a different way by making a different note the root note. That means a different note is emphasized as "home base", and often you start and end on that note.
When we take the notes of a given kalimba and make an alternative note be the root note, we are playing in a different mode.
And the punch line: traditional karimba music uses different modes, just like modern music does. And just why is that special?