You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I want to book a economy class. Could you help me in booking?

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

USER: My travelling dates are from Jan 23-25.

ASSISTANT: Ok, may I know your nearest airport codes?

USER: My airport codes are from DCA to ATL.

ASSISTANT: Do you have any limits on number of connections?

USER: No.

ASSISTANT: Do you have any another specifications on this journey?

USER: No.

ASSISTANT: May I know your name for the documentation purpose?

USER: Catherine Hill here.

ASSISTANT:  Unfortunately, no flights available on your requirements.

USER: That's ok, no problem. Thank you.

ASSISTANT: Welcome, thank you for reaching us.