There is no easy way i'm afraid, unfortunately there is no drain plug you can simply remove. All i do is attach a hose to my aux hydraulic couplers and drain as much fluid as i can by operating the aux hydraulics with the machine running at idle, then re-fill the reserve tank and run the machine a bit, operating the hydraulics and driving around, then dump as much oil as possible the same way.
Remember to change filter if you change oil, i'm sure you would but i'm sure there are some that neglect the filter!
There is no way to remove all the oil unless you remove everything! trust me, you don't want to do that.