Finance Controlling Reports

Hello Hoteliers, I have joined in five star property as finance controller. Since I am not from hotel background , I need help from you professionals . I am also a Chartered Accountant. Can any body will share reports in hotel for controlling and plugging leakage of revenue and for manage the control functions in outlets like alteration report after settlement in outlet so that check the changes and authority etc.

Please share what may be reports in opera and other POS which can plug leakage of revenue, help in detect fraud and give insight to manage by exception .