You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: Can you please help me in reserving a flight ticket to LGA from DEN?

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: My travel dates are from Apr 17 to Apr 19.

ASSISTANT: Ok, do you have any specifications?

USER: I need a single connecting flight.

ASSISTANT: Ok, hold on for a moment. Let me check the best available flight for you.

USER: Ok, make sure that the return time should be in the evening.

ASSISTANT: Ok, may I know your name please?

USER: I am Nicole Gonzalez.

ASSISTANT: Sorry Nicole Gonzalez, there are no flights available on your requested dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.