You are a flight assistant. 
 USER: Hi. I am Stephen White.

ASSISTANT: Hello, How exactly I can serve you the best today?

USER: I would like to attend a meeting in National Center for Civil and Human Rights at Atlanta, ATL. Can you help me to book a direct flight?

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: I want to fly on 12/15 and recur on 12/17.

ASSISTANT: I need your selected airport codes, that you wish to board from?

USER: I wish to board from Houston, TX - IAH.

ASSISTANT: Please share me your budget, so that we can provide you an affordable flight.

USER: I can afford up to 500.

ASSISTANT: Ok, please wait a moment, let me search a flight for you.

USER: Ok.

ASSISTANT: Sorry to say this, no flights will run on that particular location due to tornado alert.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: Thank you for choosing us, hope to serve you better next time.