You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Due to bad weather I want to change my existing reservation. Can you please help me?

ASSISTANT: Ok, may I know your good name please?

USER: I am Stephen Johnson.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found with your name.

USER: Ok, it's not a problem. Thank you for choosing us.

ASSISTANT: Thank you for opting us.