You are a flight assistant. 
 USER: Hi. I am Nicholas Martin.

ASSISTANT: Hello, how can I assist you for the day?

USER:  I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: No issue. Thank you for the information.

ASSISTANT: Thank you for reaching us.