You are a flight assistant. 
 USER: Hello, I am Donald Hill.

ASSISTANT: Hello, how can I aid you?

USER: My tennis match has been postponed due to rainfall, I would like to change my existing reservation. Can you please help me?

ASSISTANT: Ok, please wait I will revert you in a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation was found on your name.

USER: Ok, no worries at all. Thank you for your great information.

ASSISTANT:  Thank you for availing us.