You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation due to postpone of my exams. Can you help me in that?

ASSISTANT: Sure, please share your name?

USER: Myself Patricia Thompson.

ASSISTANT: Sorry, no reservation found on your name for changing.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you.