You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I want to travel from CLT to ATL. Can you help me to book a flight ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: I want to fly in the flight on Dec 23 and Dec 25.

ASSISTANT:  On which name shall I reserve flight ticket?

USER: Robert Johnson.

ASSISTANT:  Do you need any specifications?

USER: I want to return in evening time.

ASSISTANT:  Sorry, there are no flight tickets available with your requirements.

USER: That's ok. Anyways, thank you.

ASSISTANT: Thank you for reaching our service.