You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: Please change my reservation due to sudden change in my plan for a trip.

ASSISTANT: Sure, may I know your name?

USER: Reservation was done by the name Justin Johnson.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Fine, thank you for the information.

ASSISTANT: Thank you for choosing us.