You are a flight assistant. 
 USER: Hello. I am Nancy Evans.

ASSISTANT: Hello, How can I assist you?

USER: Can you help me to change my existing reservation due to postpone of my exams?

ASSISTANT: Sure, Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, no worries at all.

ASSISTANT: Thank you for opting us.

USER: Thank you.