change one's tune
CHANGE ONE'S MIND, do a U turn, have a change of heart, do an about turn

[TahlilGaran] Dictionary of Contemporary English ▲

change tune
change (your) tune
to change your opinion completely, especially because you know it will bring you an advantage.
He was against the idea to start with, but he soon changed his tune when I told him how much money he'd get out of it.

[TahlilGaran] English Idioms Dictionary ▲

change one's tune
to make a change in one's story/statement/opinion/policy
Our supervisor has changed his tune recently and agrees that we need to do things differently.

[TahlilGaran] English Idioms Dictionary ▲

change one's tune
v. phr., informal To make a change in your story, statement, or claim; change your way of acting.
The man said he was innocent, but when they found the stolen money in his pocket he changed his tune.
Bob was rude to his teacher, but she threatened to tell the principal and he changed his tune.
Synonym: SING A DIFFERENT TUNE.

[TahlilGaran] English Idioms Dictionary ▲