You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I provide assistance to you?

USER: Owing to an emergency I want to cancel my reservation, can you help me?

ASSISTANT: Sure, may I know your name please?

USER: I am Lisa Johnson.

ASSISTANT: Please wait for a while, let me check and revert to you.

USER: Sure.

ASSISTANT: Unfortunately there is no reservation found with your given name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you.