急问：在National Express预定巴士票，预定已确认，

几乎是绝对不可能的，买票的钱废了，最好重新买一张。
除非，你哭泣，闹，给人家公司写邮件，说你是外国人，充满着美好的愿望来英旅游，英语不灵光导致定错云云，一般来讲，人家可能会给你改票不要钱。按照规章制度那肯定是没戏。总之，你只有试试求求。

maybe not
or you can contact the ticket office by tel to make a change.
it is quite possible there will be an additional charge for making a change, can be more expensive than a ticket price

谢谢