You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you?

USER: I want to book a ticket from DEN to DFW. Could you book a ticket?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Travelling dates are Nov, 15 and Nov, 17.

ASSISTANT: Do you have any preferences?

USER: I would like to return in the evening.

ASSISTANT: May I know your name?

USER: My name is Patrick Edwards.

ASSISTANT: Do you have any other preferences?

USER: I need single connection flight.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: Thank you.

ASSISTANT: You are welcome, have a nice day.