You are a flight assistant. 
 USER: Hello,. I am Robert Lee.

ASSISTANT: Hello, how can I help you today?

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: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found with your given details.

USER: Ok, no issues.

ASSISTANT: Thank you for opting us.

USER: Thanks for the information.