You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Sandra Hall.

ASSISTANT: How can I assist you today?

USER: I am planning to visit  New York, will you help me in booking the flight ticket from DEN to JFK?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: My preferable journey dates are Sep 26 and Sep 28.

ASSISTANT: Do you have any specifications?

USER: I need a flight with single connection which return in evening time.

ASSISTANT: Do you have any other preferences?

USER: No, thank you for asking.

ASSISTANT: Please give me a moment.

USER: Ok, I will wait for you response.

ASSISTANT: Thanks for waiting, there is no flights found under your preferable details.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Welcome, have a great day.