You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I want to change my existing reservation due to sudden postpone of my exams dates, Can you help me out?

ASSISTANT: Sure, I will help you. Please help me with your name.

USER: I am Nicole Collins.

ASSISTANT: Please allow me a minute.

USER: Sure.

ASSISTANT: I am really sorry to inform you that there is no booking found on your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Nicole Collins, thank you for reaching us. Have a great time.