Modal shifts modify the tonal structure of a chord progression by temporarily changing its scale mode—such as moving from major to minor or introducing modes like Dorian or Mixolydian. This adjustment changes the relationships between the chords, often altering tension, resolution, and overall mood. In turnarounds, modal shifts are particularly effective at creating dynamic resolutions, as they alter the listener’s expectation of harmonic closure, adding sophistication and intrigue to the progression.