You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do to make your experience better with us?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, I'll try to help you in changing an existing reservation. Please let me know your name to check the reservation status.

USER: Sure, I am Donna Young.

ASSISTANT: Thank you for providing your name, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, there is no active reservation have been found under your name in our database to change it.

USER: Ok, not an issue. Thank you for choosing us.

ASSISTANT: Thank you for approaching us.