When a passenger asks to change their reservation to an earlier flight， you should：

When a passenger asks to change their reservation to an earlier flight， you should：
A.Immediately say no.
B.Check if there are seats available on the earlier flight and inform the passenger.
C.Tell them it's impossible without checking.
D.Just change it without confirmation.
正确答案：B
试题解析：面对乘客更改到更早航班的需求，客服应先查询是否有可用座位，再告知乘客相关情况。