感谢各位热心回复，先取消再订应该是正确的做法，估计不会收费。我是看到飞客有两个帖子都提到了订21天以后里程票然后电话改签规避近期费的事情，于是想要试一下，本来觉得不成功也不会有什么损失。改签前一时懒得打电话，想客服用的系统肯定不会比我们的差，我这里手机显示补交75美元近期费，打电话给美国客服应该也不会有差别，想想算了吧，于是一个按键下去直接扣了改签费和近期费共计150美元，这大概叫偷鸡不成蚀把米。
我是美联航普通会员，平时飞天合联盟，几年中偶尔几次坐国航深航积累了一些美联航里程。本来也知道这个75美元近期费省不了，但是这个改签费交的莫名其妙。我估计这个很难要回来了，跟这些大公司打交道对方随便扔出来一个规定你就无话可说。但是从订票时我对的24-hour flexible booking policy理解来看，应该不收费。我捡重点翻译一下，欢迎指正。
24-hour flexible booking policy
United's 24-hour flexible booking policy allows the flexibility to make changes to select reservations within 24 hours of purchasing your ticket, without incurring change fees if you made your purchase one week or more prior to the original scheduled departure flight（如果你购买的新票在原机票出发时间前一周或更早）. This includes canceling your reservation and requesting a 100% refund of the ticket price. Although Basic Economy reservations are not eligible for changes within 24 hours（尽管基本经济舱在预定24小时之内不可以更改——但是我明明看到有change选项并且顺利change，怎么回事？）, they are still eligible for a full refund if you cancel within 24 hours and you made your purchase one week or more prior to the original scheduled departure flight. Please view the terms and conditions below.
Terms and conditions
Applies to tickets booked through United Airlines.
The 24-hour time frame begins at the time your ticket is purchased.
Requests for refunds will be credited back in the original form of payment, with the exception of purchases made with a United Gift Certificate, which will be credited back in the form of electronic travel certificates.
Group tickets and tickets purchased using Western Union, cash or e-certificates are excluded.
Reservations that are being held but have not yet been purchased are excluded.
Any FareLockSM fees paid to hold a reservation will not be refunded.
