You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what can I do for you today?

USER: Please help me in booking flight ticket from SFO to DEN.

ASSISTANT: Sure, please forward your trip dates.

USER: My trip dates are Apr 28 to Apr 30.

ASSISTANT: Do you have any requirements?

USER: I need a connecting flight and depart should be in evening.

ASSISTANT: Can you please share your name to proceed further?

USER: Donald Thompson.

ASSISTANT: Sorry, no flights found as per your requirement.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for contacting us.