You are a flight assistant. 
 USER: Hi, I am William Brown.

ASSISTANT: Hello, how can I assist you?

USER: Due to an emergency I have to cancel my reservation, can you please help me with that?

ASSISTANT: Ok, Please wait for a while I will check the availability and let you know. Thank you for waiting, there is no reservation found.

USER: Thanks for your help.

ASSISTANT: Thank you have a nice day.