You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I assist you?

USER: My friend birthday party place has been changed to Los Angeles. Can you please change my existing reservation?

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting.

USER: Ok.

ASSISTANT: Sorry, we could not found any reservation.

USER: No problem.

ASSISTANT: Can I know your name, please?

USER: I am Matthew Johnson. Thanks for the information.

ASSISTANT: Thanks for reaching us.