You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Samantha Harris here. I just want to change my existing reservation. Can you please help me out?

ASSISTANT: Sure, please wait for a moment.

USER: OK.

ASSISTANT: Thanks for waiting, no reservation found with your name to change the reservation.

USER: Its OK. Thank you for the information.

ASSISTANT: Thanks for approaching us.