You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: I want to cancel my sister's reservation because she have exam next month. Can you please help me?

ASSISTANT: Sure, I am here to aid you. Can you please tell me your sister's name?

USER: Her name is Sarah Collins.

ASSISTANT: Ok, please wait a minute. I will check and get back to you.

USER: Sure.

ASSISTANT: Sorry to inform you that, there is no reservation found on your sister's name in our database  to cancel.

USER: No problem, thank you for checking.

ASSISTANT: You are welcome.