You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Myself Matthew Clark.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Thanks for your time, there is no active reservation found in your name.

USER: Not an issue. Thank you.

ASSISTANT: Thanks for your approach.