You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation due to postpone of my exams, so can you help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name to proceed further?

USER: My name is Elizabeth Taylor.

ASSISTANT: Will please wait for a while.

USER: Sure.

ASSISTANT: Sorry Elizabeth, there is no reservation found on your name.

USER: Not a problem, thanks for checking.

ASSISTANT: Thank you for choosing us.