You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I help you today?

USER: I'm Charles Rodriguez. Please change my existing reservation, owing to an emergency.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, sorry to say that, no reservation was found with your good name.

USER: Thanks for the help.

ASSISTANT: Thank you for reaching us.