You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Dennis Hall.

ASSISTANT: How may I help you?

USER: I would like to book a flight ticket with economy class.

ASSISTANT: Please share me your source and destination codes.

USER: Sure, my airport codes are HOU and AUS.

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My travelling dates are Mar 18 and Mar 20.

ASSISTANT: Do you have any other specifications?

USER: Yes, I want to return in the afternoon.

ASSISTANT: Sorry for this inconvenience, I could not find any flight with your requirements.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for reaching us.