換える
かえる · kaeru · JLPT N3 · verb-ichidan
to exchange
💱 Kaeru sounds like frog (蛙); a frog trades one lily pad for another
換 has the hand radical 扌, so things change hands. You see it in 乗り換える (norikaeru, to change trains) and 交換 (koukan, exchange). Other kaeru: 変える means to alter a thing; 換える means to swap one thing for another.