Contact the manufacturer of the sealer and ask if they have a product that will remove their sealer, or if you will just have to wait a couple years. They make grout stains to change the color and at the same time applying the stain also seals the surface for practically a lifetime......(they say).
Many brands of grout stain, AquaMix is one that is well known.
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.
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