You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I oblige you at this moment?

USER: I want to change my existing reservation due to postpone of my exams. Can you help me in that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know, on what name the ticket has been reserved?

USER: Myself George Lee.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no active reservation found on your name in the database.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.