The hot and cold is reversed on my one handle kitchen/bathroom sink faucet. What can be done to correct this?

If your faucet uses a 1225 cartridge, then the handle can be removed and the stem of the cartridge can be rotated 180 degrees (either clockwise or counter-clockwise) and reinstalling the handle. Another option would be to reverse the supply lines feeding the faucet. If your faucet uses either the 1255 or 4000 cartridge, then the only option would be to reverse the supply lines feeding the faucet.