You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I need to book a ticket from MSP to DEN. Could you book a ticket?

ASSISTANT: Sure, please share me your travelling dates?

USER: Travelling dates are from Apr, 17 to Apr, 19.

ASSISTANT: Do you have any class preference?

USER: I am comfortable with any class preference.

ASSISTANT: Is there any connection limit?

USER: I prefer connecting flight.

ASSISTANT: May I know your name?

USER: My name is Charles Collins.

ASSISTANT: Sorry, there were no flights with your given details.

USER: Thank you.