Modal interchange is a musical technique where a piece of music shifts between different modes while maintaining the same tonic or root note. This allows composers to introduce new colors and emotions into their music without changing the overall key. For example, a song in C major might borrow chords from C minor to create a contrasting section. This technique is commonly used in various genres, including jazz, rock, and classical music. By incorporating elements from parallel modes, musicians can enhance their compositions, making them more dynamic and interesting. Modal interchange enriches the harmonic palette and provides fresh musical ideas.