[change] {one's} tune
1
to change one's opinion, attitude, or way of speaking, usually to something very different from before
The idiom "change one's tune" is believed to have originated in the 14th century. It is thought to have come from the practice of minstrels who would change the words of their songs to suit their audience. If a minstrel was performing for a king or other important person, they would sing songs that were flattering and respectful. However, if they were performing for a group of commoners, they would sing songs that were more lighthearted or even bawdy. This idiomatic expression is used to describe someone who has changed their opinion or stance on a particular issue.
- He bragged that the test was easy, but when he saw his grade he changed his tune.
- He was against the idea at first, but he changed his tune after hearing the benefits.
- The politician changed her tune once she realized how popular the new law was.
- Don't expect him to stick to his word — he changes his tune all the time.
- After the meeting, the manager changed his tune about the project's feasibility.