You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I serve you?

USER: Will you please be my helping hand in changing an existing reservation?

ASSISTANT: Sure, to check reservation may I know your name?

USER: I am Jeffrey  Campbell.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: We are sorry to say that there is no reservation found with your name.

USER: It's ok, thanks for the information.

ASSISTANT: Thank you for choosing us.