You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I am Helen Carter. I would like to change my existing reservation, can you please change my existing reservation?

ASSISTANT: Sure, we are here to help you. Please hold a moment.

USER: Sure.

ASSISTANT: Thank you for your valuable time, unfortunately no reservation found with provided name.

USER: Ok, no issues at all. Thank you for your great information.

ASSISTANT: Thank you for reaching us.