You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I need your help to change my existing reservation.

ASSISTANT: Sure, can I know your name please?

USER: My name is Gary Hernandez.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry Gary, there is no current reservation found for your details.

USER: That's really sad. Anyways, thank you for the information.

ASSISTANT: Your welcome.