Drain/flush coolant on a 04 S250??????

[bildo]

Hey all i am new to the maintenance game on Skid steers. I bought a used 2005 S250 Turbo/High Flow and its been sitting for atleast 1 full year and atleast 3 years of around 100 odds hours of use.....I am changing filters/fluids...repairs if needed...I can't find any way to drain the coolant? Anyone have some thoughts or ideas on how to do this???? Please help