change up

1. verb To alter or switch something, especially from a usual method or proceedings. In this usage, a noun or pronoun can be used between "change" and "up." I've had this haircut for a while now, so I think it's time to change it up. You should change up your material so people don't get bored with it. Why would I change up the style of design that's made me famous?

2. verb To change to a higher gear while driving. You'll probably need to change up once you get on the highway. Why are you changing up? You need to change to a lower gear while climbing a hill like this. I'm sorry, I've never driven a stick before—I don't know when to change up and change down!

3. noun In baseball, a pitch that has a similar wind-up to a fastball but travels much slower. In this usage, the phrase is usually written as one word. If you throw a changeup now, I think you'll get this guy out. He hit the changeup weakly back to the pitcher and got thrown out at first. I doubt Miller was expecting a changeup after that fastball and that's why he swung and missed.

change up

1. To alter something: The cafeteria changed up the menu after people complained that they were tired of macaroni and cheese. When the other team discovered our strategy, we had to change it up.

2. To switch to a higher gear when driving a motor vehicle: When you accelerate, you have to change up or the car will stall.