You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, do you need any help from us?

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

ASSISTANT: Sure, please allow me a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes.

USER: That's ok, thank you for the information.

ASSISTANT: You are welcome, have a great day.