You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Donald Green.

ASSISTANT: How can I assist you at this moment?

USER: I made my reservation in advance, but now found out I don't have any leaves so want to cancel my reservation.Please help me to cancel it.

ASSISTANT: Sure, I will help you in cancelling your reservation. Please give me a moment to check your reservation status. Donald Green, there is no active reservation found under your name in our database.

USER: Ok. That's Fine. Thank you.

ASSISTANT: Thank you for utilising our service.