You are a flight assistant. 
 USER: Hello, I am Betty Taylor.

ASSISTANT: Hello, how can I amend you today?

USER: Can you please assist me in booking a flight ticket as I am planning to meet my grand parents after long days at Washington, IAD?

ASSISTANT: Sure, may I know your travelling dates?

USER: My planned dates of journey is 12/23 to 12/25.

ASSISTANT: Let me know your source code.

USER: San Francisco, SFO is my starting point of journey.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no flights found on your given requirements.

USER: It's ok, no problem. Thank you for your kind information.

ASSISTANT: Thank you.