You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am David Wright, I would like to make a reservation from OAK to DEN to meet my Best friend after a long time. Can you please help me to make a reservation?

ASSISTANT: Sure, may I know your journey dates?

USER: Sure, my journey dates are 12/11 to 12/13.

ASSISTANT: Ok, may I know your budget?

USER: Sure, my budget is 500.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: No issues, thanks for your service.

ASSISTANT: Thank you for choosing us.