You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Emily Carter.

ASSISTANT: How can I assist you?

USER: I need to change my existing reservation, as my exam got postponed.

ASSISTANT: Ok.

USER: Please help me in changing?

ASSISTANT: Sure, I will help you. Please, wait for a while.

USER: Ok.

ASSISTANT: Thanks for being patience. Sorry to inform you that, there is no reservation found on your name.

USER: Ok, no issues. Thank you for your service.

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