sing a different song

Related to sing a different song: sing a different tune

sing a different song

To change one's opinion, behavior, or attitude, especially suddenly or abruptly. He never used to support that political candidate, but he's singing a different song all of a sudden. I used to be very cynical about the world, but ever since surviving that car wreck, I've been singing a different song! They'll be singing a different song after they see what we've come up with.
See also: different, sing, song
Farlex Dictionary of Idioms.

sing a different ˈsong/ˈtune

(be forced to) change your opinion: Anne says she wants a large family but I’m sure she’ll be singing a different tune when she’s had one or two children.
See also: different, sing, song, tune
Farlex Partner Idioms Dictionary
See also:
  • change one's tune, to
  • sing a different song/tune
  • sing a different tune
  • sing another tune
  • backpedal
  • abortive action
  • be living on borrowed time
  • pull the rug (out) from under (someone)
  • pull the rug from under someone/something
  • pull the rug out from under