Re-Pot Bougainvillea?

Bougainvilleas do not make a good strong rootball so they are hard to repot. If you turn the pot upside-down to shake the rootball out like you would another normal potted plant, a Bougainvillea rootball will fall apart, and the plant will most likely die. I do not know what type of pot your Bougainvillea is in, but if possible I would cut off the bottom of the pot, then place the bottomless pot inside the new one. Next slice the old pot straight down the sides in 3 or 4 places. Then peel off the pieces of the sides. Once the old pot is removed, fill in fresh potting soil between the old roots and the new pot's walls. Use your fingers to push the new soil fimly into the spaces so as not to leave any air pockets. Move the pot carefully into the spot you have chosen for it, and water it thoroughly.