How to delete (remove) a approval procedures templates ?

I have added an approval procedures template for 2 stages for Good Receipt PO.

then we used this approval procedure for several days.

recently , our manager hopes me to remove this approval procedure. ╮(﹀_﹀")╭

I have tried many methods to delete (remove) or stop this approval procedure.

but , I still can not find out the solution.

hope somebody can kindly give me a suggestion. :P