I'd like to book a return flight to Shanghai this weekend.
我想订一张周末往返上海的机票。
A Can I help you, sir?
A 先生，您需要什么？
B I'd like to book a return flight to Shanghai this weekend.
B 我想订一张周末往返上海的机票。
A And when would you like to travel?
A 您想什么时间走？
B I'd like to leave Friday evening. Anytime after five o’clock.
B 我想在周五晚上走。5点以后的任何时间都可以。
A Certainly. And the return flight?
A 当然。返程呢？
B I'd like to return Sunday evening or early Monday morning.
B 我想周日晚上或者周一早晨返回。

Notes注释
1 When booking flights, you need to know where and when you want to travel and return: I'd like to book a return flight to Shanghai this weekend. / I'd like to book a return flight to Shanghai this weekend. / I'd like to leave on Friday evening. / I'd like to leave on Friday evening. / I'd like to return on Sunday evening. / I'd like to return on Sunday evening.
当预定飞机票时，你需要知道你想去何地，何时走，何时返回：I'd like to book a return flight to Shanghai this weekend. /我想订一张周末往返上海的机票。/ I'd like to leave on Friday evening. /我想在周五晚上走。/ I'd like to return on Sunday evening. /我想周日晚上返回。
2 To help someone make travel plans, you can ask: When would you like to travel? / When would you like to travel?
要帮助某人制定旅行计划，你可以问：When would you like to travel? /您想什么时间走？

Key phrases and sentences
Can I help you, sir?
I'd like to book a return flight to Shanghai this weekend.
And when would you like to travel?
I'd like to leave Friday evening.
Anytime after five o’clock.
Certainly. And the return flight?
I'd like to return Sunday evening or early Monday morning.

先生，您需要什么？
我想订一张周末往返上海的机票。
您想什么时间走？
我想在周五晚上走。
5点以后的任何时间都可以。
当然。返程呢？
我想周日晚上或者周一早晨返回。