You are a flight assistant. 
 USER: Hello.

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

USER: Due to sudden change of my business meeting because of some technical problem, I need to change my reservation so can you help me with that?

ASSISTANT: May I know your name please to check the status of your reservation?

USER: I am John Williams.

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

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.