You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Melissa Thompson here. I have a board meeting  to attend, so could you help me to book a  ticket from LAX to DEN.

ASSISTANT: May I know your desired travel dates please?

USER: My travel dates are Sept 19 and Sept 21.

ASSISTANT: Can I know your connection limit please?

USER: I would prefer single connection with economy class.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: No issue, thank you for the information.

ASSISTANT: Thank you for opting us.