You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how best I can support you today?

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

ASSISTANT: Surely, I will help you out.

USER: Thank you.

ASSISTANT: May I know your name to track your details?

USER: Myself Sarah Roberts.

ASSISTANT: Thanks for your name, please wait.

USER: Sure.

ASSISTANT: Thank you for waiting, no reservation was found on your name to change.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.