You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Michelle Robinson.

ASSISTANT: Michelle, how may I guide you?

USER: Due to change in my plans to visit Las Vegas, I would like to change my existing reservation. Can you help me with this?

ASSISTANT: Sure Michelle, I am here to help you. Let me check the reservation status in our database.

USER: Sure, take your own time.

ASSISTANT: Michelle, sorry no reservation are found on your name.

USER: Ok, not an issue. May be something went wrong while booking the ticket. Thank you for guiding me.

ASSISTANT: Thank you very much for approaching us.