You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Could you please change my existing reservation due to postpone of my exams?

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

USER: My name is Gregory Lewis.

ASSISTANT: Thank you. Please be online for a while. I will check your reservation status and get back to you.

USER: Sure.

ASSISTANT: I am sorry to say you that there is no reservation found under your name in our database.

USER: Not a problem, thank you.

ASSISTANT: Thank you for reaching us.