the music changed

Instantly the music changed....  --Pierre: Or, The Ambiguities (1852)

Southern Literary Messenger - May 1853

But soon, the music changed; and, stranger then and there, to a sweet waltz!  --May 1853 Scenes Beyond the Western Border; and Scenes and Adventures in the Army (with "sweet waltz" revised to "joyous air").

Scenes and Adventures in the Army (1857) - page 409