You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, tell me how may I help you?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Can you please tell me your name for searching your existing reservation?

USER: I'm Shirley Clark.

ASSISTANT: Sorry to say, no flight found on your name.

USER: OK.Not an issue. Thank you for your information.

ASSISTANT: OK, thank you for contacting us.