You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Williams Miller.

ASSISTANT: How can I assist you today?

USER: I am looking for a flight from Houston, can you book me the flight ticket from IAH to CLT?

ASSISTANT: Sure, will you mention your travelling dates that you want to travel?

USER: My travelling dates are 21st December and 23rd December.

ASSISTANT: Do you have any specifications?

USER: I need an economy class flight.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no flights found under your preferable details.

USER: That's ok, not an issue. Thank you for your information.

ASSISTANT: Welcome, have a great day.