You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, give me a minute.

USER: Ok.

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

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching us.