A portable basketball hoop's base is filled with water or sand specifically so it will not tip over during a game, which also means it is far too heavy to tip over on purpose during a move. Drain it first and the rest of the system comes apart easily.
Pro tip: Fill a sand base with pea gravel instead next time; it weighs less than sand for similar stability and is far easier to scoop out for a future move.
Watch out: Never tip a portable basketball hoop with the base still filled; a full water or sand base can weigh over 300 pounds and the whole assembly can crush a foot or crack a driveway if it falls.