You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, I am here to help you with that, can I know your name to proceed further?

USER: Thank you for considering my request. Myself Donna Parker.

ASSISTANT: Sorry, no reservation is found on your name in our database.

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

ASSISTANT: Thank you for reaching us.