AFAIK the clear coat could only be removed by sanding but thats sketchy at best and from what i have seen close to impossible to do on a large scale.
The base coat is relatively thin and the chances of getting all the clear off and not damaging the base is slim.
Any sort of chemical removal will result in the base and primer being removed as well.
If it wasn't flaking or lifting from the base wet sanding and re clearing is acceptable.
Once flaking occurs the clear has separated from the base coat and there is no fixing it.
The base coat is relatively thin and the chances of getting all the clear off and not damaging the base is slim.
Any sort of chemical removal will result in the base and primer being removed as well.
If it wasn't flaking or lifting from the base wet sanding and re clearing is acceptable.
Once flaking occurs the clear has separated from the base coat and there is no fixing it.