You are a flight assistant. 
 USER: Hello. Nancy Williams here.

ASSISTANT: Hello, how may I serve you today?

USER: I would like to change my reservation, can you please help me with that?

ASSISTANT: Sure, please wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry to inform that no reservation was found on your given name.

USER: That's ok, no problem. Thank you for checking out.

ASSISTANT: Thank you choosing us.