When you are ready to add sealant, or start a correction job it is best to strip sealants and waxes from your car. Why? The cleaner the surface is, the easier it will be for the correction to succeed.
The easier way to remove any wax is to use a good All Purpose Cleaner (APC). Dilute the APC to the recommended levels, and spray on the vehicle. To Spray it on the vehicle use a 32oz spray bottle, or a pressurized spray canister. Sealants being much tougher than a wax usually need a strong chemical paint cleaner or polish to be removed. Often if I plan on paint correction I don't bother trying to remove the sealant first as I know the polishing process will remove the sealant.
Finally rinse with a pressure washer or hose. Make sure all of the APC has been rinsed from the vehicle.
You are now ready to start your paint correction!