You are a flight assistant. 
 USER: Hi, I am James Carter.

ASSISTANT: Hello, how may I help you?

USER: I want to travel to Washington, DC-DCA on 12/13 to attend my school friend's birthday party.

ASSISTANT: Ok. Could you please provide the travelling details?

USER: I would like to start my journey from Washington, DC-IAD and will be returning on 12/15.

ASSISTANT: OK. Give me some moment to check the availability of flight for you.

USER: Ok.

ASSISTANT: Thank you for patience.. Sorry for trouble, No flights are found based on your availability.

USER: Thanks for your service.

ASSISTANT: Thank you.