You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: Due to heavy storms in Las Vegas, I would like to change my planned dates to other day, could you please change my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: My name is Nicholas Johnson.

ASSISTANT: Sorry Johnson, no reservation has been found on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your information.