You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you/.

USER: I am Richard Allen. I would like to attend a seminar at Detroit, MI-DTW on 12/20. Could you please help me with booking a direct flight?

ASSISTANT: Sure, we are here to help you. Let me know when you are willing to travel?

USER: I would like to return on 12/22.

ASSISTANT: May I know your source point?

USER: My origin airport is Houston, TX-IAH.

ASSISTANT: Ok, wait for some time I will check and get back to you.

USER: Sure.

ASSISTANT: Thanks for waiting there is no flights found on your details.

USER: No problem, thank you for the information.

ASSISTANT: Thanks for approaching us.