You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How may I support you?

USER: I am Stephen Moore.

ASSISTANT: Ok.

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not found any active reservation on your name to change.

USER: No problem, thank you.

ASSISTANT: Thank you for contacting us.