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

ASSISTANT: Hello, how may I assist you today?

USER: Due to the illness of my granddad, I am unable to catch a flight. So please cancel my recent reservation?

ASSISTANT: Sure, I will help you. Please wait for a while, I will check and get back to you.

USER: Sure.

ASSISTANT: Thanks for your time, sorry, there is no reservation found on your given name.

USER: Ok, no worries at all. Thanks for your kind service.

ASSISTANT: Thanks for choosing us.