You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Sure, may I know your name?

USER: Myself Dorothy Williams.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

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

USER: Not an issue. Thank you.

ASSISTANT: Thank you.