波鞋太大??點算??

我買左一對white波鞋.(go to school 的）
我發現a pair 鞋部分太大　
我本身wear 5.5uk but i but 6.5uk it is so big .
I only are P.6 student not too tall .
有咩方法可以令到對鞋變small

Thank you very much .