You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to change my existing reservation, please help me out.

ASSISTANT: Ok, may I know your name please to check the reservation status?

USER: Sure, my name is Betty Wilson.

ASSISTANT: Betty, there is no reservation found with your details.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for utilising our services, hope you visit us again.