1) The 'right' way - stand mower on some sort of raised platform so you can work underneath it. DISCONNECT SPARK PLUG, then remove the drain plug from bottom of engine - similar to a car. Drain oil (hot), replace plug and refil.
2) The 'easy' way - remove oil filler and physically tip mower up to drain oil through the filler. This works best if the engine has a dipstick - easier to catch the oil!
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