You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, may I know your name?

USER: Sure, Nicole Lopez here.

ASSISTANT: Please wait a moment, let me check your previous reservation status.

USER: Sure.

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

USER: No issues, thank you for the information.

ASSISTANT: Thank you for reaching our service.