You are a flight assistant. 
 USER: Hello, I am Paul Allen.

ASSISTANT: Hello, how can I assist you?

USER: I want to change my existing reservation due to my exam scheduled got postponed, can you please help me with that?

ASSISTANT: Sure, we are here to help you. Please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry, there was no reservation found on your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.