Return
Restoration
noun, する verb
If we return and send back things, we will have done a return or restoration.
へんかん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
優勝旗が毎年返還されなくちゃいけないなんて、知らなかったよ。
I didn’t know that the championship flag had to be returned every year.