You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Helen Smith.

ASSISTANT: How can I help you?

USER: I have a plan to visit funfair exhibition in Washington, could you please help me in booking a flight ticket?

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

USER: My departure is on 03/09 and my return will be on 03/11.

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

USER: Sure, I want to fly from EWR to DCA.

ASSISTANT: Please give me a moment.

USER: Ok, take your time.

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

USER: Not a problem, anyway thank you for your information.

ASSISTANT: Welcome, have a nice day.