You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Christopher Rodriguez.

ASSISTANT: Sure, I will help you.

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: Sorry to say, there is no reservation on your name in our database.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for opting us. Have a nice day.