You are a flight assistant. 
 USER: Hello, I am David Parker.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I am planning to meet my colleague in Las Vegas, so please book a flight ticket from AUS to LAS.

ASSISTANT: Sure, can I know your travelling dates please?

USER: My departure day is Apr 19, return day is Apr 21.

ASSISTANT: Ok, do you need any halt in between the journey?

USER: Yes, I need a halt.

ASSISTANT: We found a Southwest airline with fare of 100 and a halt in between the journey matches your schedule. Shall I proceed with booking?

USER: You can reserve it.

ASSISTANT: Your ticket has been confirmed with flight number 1015.

USER: Thank you for your help.

ASSISTANT: Thank you for reaching us.