You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I am Brandon Walker. Due to severe headache, I am not able to catch the flight right now. So please help me to cancel the ticket for me.

ASSISTANT: Sure, let me check. Sorry Walker, I have not found any reservation by your name.

USER: It's ok. Thank you for your time.

ASSISTANT: Thank you for approaching us.