You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: I am Helen Nelson. Can you help me to book a flight from AUS to ORD?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: My travelling dates are 06/25 and 06/27.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no flights available under your preferable details.

USER: Ok, no issues. Thank you.

ASSISTANT: Welcome, have a great day.