Pry as much of the wax from the sofa using a dull-edged butter knife. Try to remove the bulk of the wax if possible. This will make it easier to remove the rest of the wax.
Place a sheet of waxed paper over the candle wax.
Lay a small towel or a stack of paper towels directly on top of the waxed paper.
Place a warm iron on top of both and iron over the towel and paper until the candle wax starts to transfer to the waxed paper from the sofa. Repeat this until the wax has been removed from the fabric.
Remove any stains caused by the candle wax using a paste of baking soda and water or a mixture of liquid detergent and water. Rub into the sofa with a damp towel to remove any remaining residue.