You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: I want to change my existing reservation. Can you help me for that one?

ASSISTANT: Sure, may I know your name?

USER: Sure, Nancy Taylor here.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Thanks for your time, we are sorry to say that there is no active reservation found on your name.

USER: No issues, thank you for the information.

ASSISTANT: Thanks for opting us, wish you a great day.