You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: Aid me in booking a flight from SFO to DEN under 500 fare.

ASSISTANT: Sure, can you share your travel dates?

USER: 10/12 and 10/14 are my travel dates.

ASSISTANT: May I know your good name?

USER: Joseph Roberts is my name.

ASSISTANT: Thank you for your details, there were no flights found in your route.

USER: Ok, then no problem. Thanks for the information.