You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you help me to change my reservation?

ASSISTANT: May I know your name?

USER: I am Nicole Johnson.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

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

USER: No problem, thank you for checking.

ASSISTANT: Thank you for reaching us.