You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I want to do some changes in my existing reservation because my exam has been postponed. Can you please help me for that?

ASSISTANT: Sure, I will help you. To proceed further may I know your name?

USER: My name is Virginia Perez.

ASSISTANT: Sorry, no reservation found with your name to change the reservation.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.

USER: Welcome.