Can you replace the surface of the Smooth PEI plate or do you have buy a new p[late?
buy a new plate and ruined how ? I bet trying to scrap pet away ? confess 
You can lightly sand textured PEI but if you damage smooth I think is toast. The one I’ve killed failed in a way that the nozzle pierced the wrap down to the steel, and it bubbled up in a cancer underneath.
If the damage is only in one zone/quadrant, you can just place objects carefully in the slicer to avoid the bad spot.
No, it just has a few pits in it.
And, never mind - Bambu says it can’t be replaced,
You can try sanding, it’s just a solid piece of PEI.
H2D need it for advanced nozzle offset, I already ruined one side, I now keep it safe with the vision encoder, I don’t print on it anymore 