You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you today?

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

ASSISTANT: Sure, can you please mention your connection limit?

USER: I would be comfortable with single stop over.

ASSISTANT: Please let me know your name.

USER: My name is Donald Perez.

ASSISTANT: On  which dates would you like to make your journey?

USER: Departure is on Apr, 14 and return date is Apr, 16.

ASSISTANT: Do you have any more specifications in your journey?

USER: I prefer to fly in a normal-cost airlines.

ASSISTANT: Sorry, there are no flights are available matching your credentials.

USER: Thank you.

ASSISTANT: Thank you for approaching us.