You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you please help me in booking a flight ticket from OAK to DEN?

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

USER: My travel dates are from Oct 18th to Oct 20th.

ASSISTANT: Do you have any class preference?

USER: Yes, I want an economy class to travel.

ASSISTANT: May I know your connection limit?

USER: My connection limit is one.

ASSISTANT: Do you have any other specification that you are looking for?

USER: No.

ASSISTANT: May I know your name to proceed further?

USER: I am Katherine Lee.

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

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for contacting us.