For quick jobs like regular blade exchanges use a pair of truck ramps.
They are higher than the normal car ones and have a flat surface so the casters do not get stuck between the rungs as on most cheapie ramps.
Pop a piece of carpet, fiber side down under the stands and they will rotate quite freely with the mower on them so you can swing them about 30 deg to get clean access to the blades on 3 blade decks, two blade decks are fine.
When finished lift each caster a little ( quite easy not much weight on them ) and rotate 108 degrees so it will roll strait off.
For bigger jobs it is a block & tackle swung off an overhanging RSJ.