Yes it can, if the competitors product is solvent based. Alliance resealer can be used over any Alliance sealers, except the Natural Look. It is always recommended to test it first in an inconspicuous place, to be sure that there are no issues. Note: A solvent sealer can be used on top of another solvent or water based sealer. However, a water-based sealer can never be used over a solvent based. If doing a solvent based resealer over one of the Alliance Hybrid sealers, the existing Hybrid sealer must be intact no bare spots otherwise there will be a difference in the finished look. For resealing we recommend our resealer again always do a small test area first.