兑换 (duì huàn) specifically means to exchange or convert currency, points, vouchers, or other official equivalents — it's the formal term for financial or point-based conversion. In contrast, 换 (huàn) is the general verb for any exchange or change (clothes, seats, money), and 交换 (jiāo huàn) implies a mutual swap between two parties. 转换 (zhuǎn huàn) means to transform from one state to another (e.g., convert energy), not a direct exchange.