change; alteration
substitute; spare; replacement; change (e.g. of clothes)
rate of exchange
タイヤの換えを用意しておく。
I prepare a spare tire.
このレンズには換えがないので大切にしたい。
There is no replacement for this lens, so I want to take care of it.
電池の換えを買い忘れた。
I forgot to buy replacement batteries.