When is a credit card transaction considered fraud?

Many times my boss at work will ask me to run a customer's credit card through without the customer's authorization. My boss will claim that a customer authorized a certain transaction. I will call the customer on the phone and find out that they never did actually authorize that purchase, or that the amount of the purchase was several hundred or thousand dollars more than what the customer actually authorized. My boss will pressure me and tell me that the customer did indeed authorize the transaction. Do I have a right to refuse to perform the transaction? We do not utilize written authorization forms. Is it considered fraud if I run the credit card through according to the boss's terms? If my boss runs the credit card through anyway, should I report this to the local authorities? Should I report past fraudulent credit card transactions to the local authorities?