You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I an Catherine Thomas. I want to travel from LAX to DCA. Can you help me in booking a flight ticket?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

USER: I want to travel in the flight on Feb 15 and Feb 17.

ASSISTANT: Do you have any specifications?

USER: I want to depart in afternoon time and return in afternoon time.

ASSISTANT: Sorry, no flights are available on your route.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.