You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How can I serve you today?

USER: I am Benjamin Miller, I want to book a flight ticket for attending a sports event in San Francisco.

ASSISTANT: Sure, may I know your travelling dates?

USER: My departure day is 11/26, return day is 11/28. Price limit is 1000.

ASSISTANT: May I know your airport codes?

USER: My source and destinations are NC-CLT, CA-SFO.

ASSISTANT: Thank you, for providing details, we are sorry to say that no flights were found with your given details.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: Thank you, for reaching us.