You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be at your service today?

USER: I am Joseph Phillips. I want to change my reservation, can you help me?

ASSISTANT: Sure, we are here to help you. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry there is no reservation found against your name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for choosing us.