Don't have a beadbreaker? Use your side-stand.
But...your wheel is off and bike immobilized...and you don't have a buddy with a bike (with a side stand)? Get creative.
I used a metal bar through a board with a drilled hole. Hooked it under an iron fence and simply levered down on the tire taking care not to scratch (too much) the rims. Place the wheel on a couple of 2x4's to have the rotor/sprocket off the ground. Good to drape a towel/cloth over the 2x4's to prevent scratching as well.