You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, may I know your name?

USER: My name is Brian Hernandez.

ASSISTANT: Sorry, there is no reservation with your given name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for reaching us.