You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: I am Carol Thomas. I want to book a flight ticket to visit a Redwood Regional Park in Oakland, could you help me in booking a flight ticket?

ASSISTANT: Sure, May I know the journey codes?

USER: My source is Washington, DC - IAD and destination code is Oakland, CA - OAK.

ASSISTANT: Please help me with your travel dates.

USER: I would like to fly on 12/17 and return on 12/19.

ASSISTANT: Sorry, No flights found with your chosen dates. Thank you for opting us.

USER: Not an issue. Thank you.