You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you at this moment?

USER: I want to change my reservation due to postponed of my exam to other dates, so please help me.

ASSISTANT: Sure, I can help you with that reservation changing.

USER: Thank you.

ASSISTANT: Please hold for a while, let me check you previous reservation status.

USER: Please check my reservation on the name of Emma Phillips.

ASSISTANT: Thank you for waiting. Sorry to tell you that, there is no active reservation found with your name in our reservation list to change it.

USER: No issues, thank you for your effort.

ASSISTANT: Thank you for reaching our agency.