You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, we are here to help you. May I know your name please?

USER: I am Amy Nelson.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for contacting us.