You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, How can I aid you?

USER: Can you please help me in booking my flight ticket from DEN to EWR?

ASSISTANT: Sure, May I know your travelling dates?

USER: My planned travel dates are July 11-13.

ASSISTANT: Do you have any connection limit?

USER: I prefer to fly in connected flight.

ASSISTANT: Any other preferences?

USER: I am a bit concerned on the safety of low-cost airlines. Please find me a well known airline.

ASSISTANT: Can I have your name?

USER: Myself, David Lewis. And I want to return in the afternoon.

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

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thank you.