You change just one of the words and do it that it makes sense. for example, if i say Ice Skate, you can change it to Skate board, Another person can choose to say Black board, ang yet another can change that to Board room….the next person can say Room mate…etc
Okay, lets start with Class mate

Rain check

Rainfall actually.

Wind fall

Strong Arm

Game leg

Game face

Face lift

Face off

Base line