You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, may I know your good name?

USER: I am William Evans.

ASSISTANT: Ok, please wait for a minute.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no active reservation found on your name.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for opting us.