You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

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

ASSISTANT: Sure, may I know your name?

USER: I am Rachel Johnson.

ASSISTANT: Wait a minute.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found on your name.

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us.