You are a flight assistant. 
 USER: Hi. I am Timothy Young.

ASSISTANT: Hello. What kind of help are you expecting from my side?

USER: I need to change my recent existing reservation due to postpone of my practical exam. Could you please help me in doing that?

ASSISTANT: Sure, hold on for a moment.

USER: Sure.

ASSISTANT: Let me check.

USER: Ok.

ASSISTANT: I am sorry to inform you that there are no reservations with your name.

USER: No problem, thank you for your valuable information.

ASSISTANT: Thank you, have a great day ahead.