idiom · to change one's mind frequently or reverse decisions that have already been settled upon; to be indecisive (literally 'three in the morning, four in the evening')

既然已经定下了计划，就不能朝三暮四，随意更改。

idiom · to blow hot and cold; to be inconstant or unreliable in one's loyalty, interests, or affections

他在感情上总是朝三暮四，这种态度很难让人产生信任感。