We have to give you your change in Japanese yen. Is that okay?
We can't give you the same currency for your change. Is that alright?
この場合、次のような言い方ができますよ。
ーWe have to give you your change in Japanese yen. Is that okay?
「日本円でお釣りを渡さなければいけませんが、よろしいですか?」
to give you your change in Japanese yen「あなたにあなたのお釣りを日本円で渡す」
ーWe can't give you the same currency for your change. Is that alright?
「あなたのお釣りを(あなたが払った)同じ通貨で渡せませんがよろしいですか?」
currency で「通貨」