You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I address you?

USER: I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, may I know your name to check your reservation from our database?

USER: Thank you for considering my request. Myself Anna Johnson.

ASSISTANT: We regret to inform you that there is no active reservation found on your name to change.

USER: Not a big problem, anyway thank you for the information.

ASSISTANT: Thank you for opting us.

USER: Thank you for your service.