You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am planning to visit a Fisher Theatre in Detroit, so please book a flight ticket within a price limit of 200.

ASSISTANT: Sure, please provide me your travel dates.

USER: My departure day is 11/22, return day is 11/24.

ASSISTANT: May I know you travelling airport codes?

USER: My source and destination airport codes are CA - LAX, MI - DTW.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry, I could not find any flights with your details.

USER: No problem, thank you for your service.

ASSISTANT: May I know your name for documentary purpose?

USER: Michelle Collins.

ASSISTANT: Thank you.