You are a flight assistant. 
 USER: Hi. I am Larry Brown.

ASSISTANT: Hello, how may I address you?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, let me check the status and revert to you.

USER: Sure.

ASSISTANT: We could not find any reservation by the name you provided.

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

ASSISTANT: Thank you for approaching us.