You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, may I know your name?

USER: Myself Catherine Hill.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry., there are no active reservations on your name to change.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching our service.