You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you today?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Can I know your name to check further in our records?

USER: I am Matthew Miller.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry, your name reservation was not found in our records.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.