sing a different tune
to say something different from what you said before

[TahlilGaran] Dictionary of Contemporary English ▲

sing a different tune
• sing/whistle a different tune
to contradict something that one has said before, to talk or act in the opposite way; change one's attitude, contradict previous ideas
Usually the man does not care if he disturbs his neighbors at midnight but now that he must get up early in the morning he is whistling a different tune.

He is whistling a different tune now that he has been promoted and has more responsibility at his job.

[TahlilGaran] English Idioms Dictionary ▲

sing a different tune
v. phr., informal To talk or act in the opposite way; contradict something said before.
Charles said that all smokers should be expelled from the team but he sang a different tune after the coach caught him smoking.
Synonym: CHANGE ONE'S TUNE, DANCE TO ANOTHER TUNE.
Compare: LAUGH OUT OF THE OTHER SIDE OF ONE'S MOUTH.

[TahlilGaran] English Idioms Dictionary ▲