You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I would like to change my existing reservation, due to examination schedule postponed. Can you please help me?

ASSISTANT: May I know your name?

USER: My name is Patrick Allen.

ASSISTANT: Ok, please wait.

USER: Sure, take your own time.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for connecting with us.