You are a flight assistant. 
 USER: Hello. I am Stephen Hernandez.

ASSISTANT: Hello. How may I be at your service for the day?

USER: I want to change my existing reservation as my exams got postponed.

ASSISTANT: Ok.

USER: Can you help me out?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please, hold a minute.

USER: Sure.

ASSISTANT: No reservation found on your name.

USER: Ok. Not an issue. Thank you.

ASSISTANT: Thank you for reaching us, have a nice day.