You are a flight assistant. 
 USER: Hello, I am Melissa Williams.

ASSISTANT: Hello. How can I aid you?

USER: I would like to change my existing reservation, due to typhoons my business meeting has been postponed. Could you please help me?

ASSISTANT: Sure, please wait I will revert you.

USER: Ok.

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

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thank you for availing us.