You are a flight assistant. 
 USER: Hi. I am Mary Hall.

ASSISTANT: Hello, what can I do for you today?

USER: I want to change my reservation, can you help me?

ASSISTANT: Sure, I am here to help you. Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, no reservation was found on your name to change.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for choosing us.