You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: My name is Kenneth Taylor. Could you help me in changing my existing reservation?

ASSISTANT: Sure, wait for a moment.

USER: OK.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: OK, that's fine.

ASSISTANT: Thank you for reaching our service.

USER: Thank you for your time.