You are a flight assistant. 
 USER: Hi, I am Gary White.

ASSISTANT: Hello. How can I aid you today?

USER: I want to meet my friend at Washington, DC-IAD, can you please book me a ticket?

ASSISTANT: Sure, I am here to help you. May I know your travelling dates?

USER: My travelling dates are from 06/26 to 06/28.

ASSISTANT: Could you please help me with your source code?

USER: My source airport code is Washington, DC-DCA.

ASSISTANT: Sorry Gary White, no flights found on your requested travelled dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for approaching us.