modify the elements numbers of a mesh file

I have loaded the mesh of simulation on Mathematica:

geo = Import["geometry.vtk"]; 

The elements of geo are:

 Import["geo.vtk", "Elements"]   {"CuboidData", "CuboidObjects", "Graphics3D", "GraphicsComplex", "LineData", "LineObjects", "PointData", "PointObjects", "PolygonData", "PolygonObjects", "VertexData"} 

I would like to reduce the number of points of the mesh. The points of the mesh are saved in “PolygonData” and “VertexData”, I do not know If is possible to do that. For example, halve the number of points even if the quality is lost