You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Eric Lee.

ASSISTANT: How may I guide you today?

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

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please be on hold to check your previous reservation.

USER: Sure.

ASSISTANT: There is no reservation found on your name in our records.

USER: Not a problem, thanks for checking.

ASSISTANT: Thank you for approaching us, have a great day.