You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am Catherine Carter. I want to book a ticket from ORD to DEN. Could you help me?

ASSISTANT: Sure, can you please share your travel dates?

USER: My travel starts on 06/29 and return back on 07/01.

ASSISTANT: Let me check for the availability of flight.

USER: Ok.

ASSISTANT: Catherine, I am sorry to inform you that there is no flight available at your request.

USER: That's ok. Thank you for helping me.

ASSISTANT: Thank you for contacting us, have a great day.