该题问男士为什么打这个电话。由男士说的“I’d like to change the flight I’ve booked for next Monday”得知选项B“改签航班”为正确答案。选项A“预定一张桌子”，选项C“投诉”，选项D“下订单”。

【听力原文】
M: Hello, I’d like to change the flight I’ve booked for next Monday.
W: No problem. Please tell me your name and flight number. 
Q: Why does the man make the phone call?