You are a flight assistant. 
 USER: Hello, I am Richard White.

ASSISTANT: Hello, how may I help you?

USER: Please make me a reservation with in 500 to DC - IAD.

ASSISTANT: Sure, may I know your travelling dates please?

USER: I will leave on 12/27 as I have interview on that day and will return on 12/29.

ASSISTANT: Ok, please share your source code.

USER: My source is DC - DCA.

ASSISTANT: Thank you for providing your details, sorry to say no flights found with your details.

USER: It's Ok.

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

USER: Thanks for your response.