You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am David Miller.

ASSISTANT: How can I assist you at this moment?

USER: I would like to cancel my brother's reservation as he is unwell, can you please help me?

ASSISTANT: Sure, I am here to help you. Please give me a moment to check your reservation status.

USER: Sure.

ASSISTANT: David Miller, there is no active reservation found under your name in our database.

USER: Ok, no issues. Thank you for helping me.

ASSISTANT: Thank you for opting us.