You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: Can you book a flight ticket from DFW to DEN?

ASSISTANT: Sure, may I know your planned travel dates?

USER: My trip is in Apr from 7th to 9th.

ASSISTANT: Do you have any limits on number of connections?

USER: I need a single connecting flight.

ASSISTANT: Do you have any another specifications on your journey?

USER: No, I don't have any other requirement.

ASSISTANT: May I know your name for the documentation purpose?

USER: Linda Lee here.

ASSISTANT: Sorry Lee, we regret to inform you that there is no flight available as per your request.

USER: That's ok,thank you for your information.

ASSISTANT: Welcome, thank you for reaching us.