You can requite a friend’s kindness by doing your friend a favor or by being kind in return. Requite means "to repay or return."
To requite something is to return it. However, saying that you want to requite a gift means that you want to give something in return for it — not that you want to return the gift to the store for some quick cash. Requite is often used in the context of love; if you requite someone’s love, you love that person back. Requite can also be used in a negative sense. Someone who wants to requite an injury wants payback for it.