You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please assist me to book a flight ticket from DEN to LGA to meet my family?

ASSISTANT: Sure, may I know your trip dates please?

USER: I have planned to travel on Feb 09th and return on Feb 11th.

ASSISTANT: Do you have any other requirements?

USER: I want to depart at afternoon time.

ASSISTANT: Can I know your name please?

USER: Samuel Brown.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: Ok, no problem. Thank you.