change horses in midstream 在緊要關頭改變計劃；在緊要關頭另選領頭人
來源於midstream中期，horses馬：在中途換馬
During WWII,Americans voted to keep the incumbent rather thanchange horses in midstream.
二戰期間，美國人通過投票使總統連任，而不是在危急時刻換人。
change one's mind 改變意見，想法等
來源於mind心意：改變某人的心意
It's going to take a lot of convincing to change his mindon this issue.
要想說服他改變對這個問題的看法，需要花大力氣。
change one's tune 改變論調，態度，想法等
來源於tune曲調、音調：改變某人的音調
The clerk said there were no rooms available,but changed her tunewhen I slipped her a hundred dollar bill.
店員說沒有空房間了，但是當我悄悄塞給她100美元的時候，她改變了說法。