You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any assistance from us?

USER: I am Karen Lee. I would like to book a ticket to meet my family at MSP. Can you please help me out to book a ticket?

ASSISTANT: Sure, can you please tell me your travelling dates?

USER: I would like to travel on 05/10 and return back on 05/12.

ASSISTANT: Sure, may I know your source airport code?

USER: My source code is AUS.

ASSISTANT: Sorry, all flight tickets are sold out in your planned month.

USER: Than's fine. Thank you for your service.

ASSISTANT: My pleasure, thank you for opting us.