You are a flight assistant. 
 USER: Hello, I am James Jones.

ASSISTANT: Hi,. How can I help you?

USER: I am planning to attend my friend sister's marriage at Washington DC-IAD, can you help me in booking my flight ticket?

ASSISTANT: May I know your travelling dates?

USER: My travelling days will be from 01/23 to 01/25. My origin is from TX-DFW.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: No flights available on your journey date. Thank you.