只有提供原始收据，商品才能换货。

Items can only be ___exchanged if you provide the original receipt.

我想把这件毛衣换成小一号的。

I'd like to ___exchange this sweater for a smaller size.

他在客服柜台将损坏的商品换成了退款。

He ___exchanged the damaged goods for a refund at the customer service desk.