You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you?

USER: I want to change my existing reservation, due to some personal problems. Can you help me?

ASSISTANT: Sure, I am glad to assist you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: My name is Joseph Evans.

ASSISTANT: Sorry Joseph Evans. Based on your name we haven't found any flight reservation in airline database,.

USER: That's fine, not an issue. Thank you for your valuable information.

ASSISTANT: Thanks for reaching us.