You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Can you help me to change my reservation?

ASSISTANT: Sure, let me know your name please?

USER: I am Dennis Moore.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name in our portal to change it.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for contacting us.