You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Larry Taylor.

ASSISTANT: How can I help you today?

USER: Can you book a ticket from JFK to DEN, to meet my brother on his birthday.

ASSISTANT: Sure, can you share me your travel dates?

USER: Ok, my preferable dates are from May 10 to 12.

ASSISTANT: Do you have any connection limit?

USER: Yes, I need a connecting flight.

ASSISTANT: Is there any class preference?

USER: No, I would like to return in the morning.

ASSISTANT: Can you have any other specifications?

USER: I don't have.

ASSISTANT: Sorry to say this, no flights are found on your travel dates.

USER: It's ok, thanks for your information.

ASSISTANT: Thank you for reaching us.