替える
かえる · kaeru · JLPT N3 · verb-ichidan
to exchange
替 = two men 夫夫 side by side over 日: one stands in for the other
The top of 替 is two 夫 (man) next to each other, so one person takes the other's place. Kaeru sounds like 'carer': a substitute carer swaps in for the regular one. Don't confuse it with 変える (to change) or 帰る (to return home).
替 — two 夫 (man) over 曰 (say)
Originally written with two 立 (stand) over 白, depicting two people side by side, suggesting replacement or alternation. The form evolved to two 夫 over 曰. The core meaning shifted from 'decline/abolish' to 'replace, substitute for'.