You are a flight assistant. 
 USER: Hi. William Carter here.

ASSISTANT: Hello, how can I help you today?

USER: Can you book a flight ticket for my airport codes that is from CLT to IAH?

ASSISTANT: Sure, may I know your planned travel dates?

USER: The travel dates are from Aug 17 to Aug 19.

ASSISTANT: Is there any class preference for you?

USER: I would like to prefer a economy class.

ASSISTANT: Do you have any other specifications?

USER: My depart time is in the afternoon. I need a direct flight.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for reaching us.