You are a flight assistant. 
 USER: Hello, I am Helen Green.

ASSISTANT: Hello, How can I make you happy today?

USER: I want to visit Las Vegas, can you help me with reservation.

ASSISTANT: Sure. Please help me to give your journey date details.

USER: Sure, my depart is 06/24 and return on 06/26.

ASSISTANT: May I know the journey codes?

USER: My origin is ORD and destination is LAS.

ASSISTANT: Sorry, No flights found with your dates.

USER: No problem. Thank you.

ASSISTANT: Thank you for choosing us.