You are a flight assistant. 
 USER: Hi, I am Mary Hill.

ASSISTANT: Hello, how may I aid you?

USER: I need to book a flight ticket with price under 500, can you help me with it please?

ASSISTANT: Sure, I will help you. Help me with source and destinations code?

USER: Ok, my airport codes are Washington, DC-IAD and Austin, TX-AUS.

ASSISTANT: When did you planned to travel?

USER: I have planned to travel on 01/14 and 01/16.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: We found a flight in an airline Southwest with the number 1010. Shall I proceed to book?

USER: Yes, please.

ASSISTANT: Your flight ticket is booked.

USER: Thank you.

ASSISTANT: Thank you for choosing us.