You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name?

USER: I am Dennis Walker.

ASSISTANT: Nice to meet you Dennis. How can I assist you today?

USER: I want a flight ticket from JFK to DEN, can you please book a ticket if it is available?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are 06/21 to 06/23.

ASSISTANT: Sorry Dennis, I cannot find any flights with your details.

USER: It's ok. Thank you for your information.

ASSISTANT: Thanks for contacting us, have a great day.