替える
かえる to exchange to interchange to substitute to replace

替え刃
かえば spare or new razor blade

替え地
かえち substitute land or lot

替え心
かえしん spare lead

替え歌
かえうた parody (of a song)

替え玉
かえだま substitute double

替え着
かえぎ change of or spare clothing

替え芯
かえしん spare lead