You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I want to participate in Arts and Crafts festival at Washington, DC - IAD. Can you please book a ticket under price 200?

ASSISTANT: Sure, I would be happy to help you. May I know when you are willing to travel?

USER: My travelling dates are 07/29 and 07/31.

ASSISTANT: Can I know your name please?

USER: Sure, I am Michael Smith.

ASSISTANT: Kindly mention your source code?

USER: My source is Las Vegas, NV - LAS.

ASSISTANT: We found a direct flight with your matching requirements. Can I proceed?

USER: Do not proceed, I need a halt.

ASSISTANT: Ok, thank you.

USER: Thank you.