A topological bistellar flip is the term used by Dougherty, Faber, and MurphyDougherty, Faber, and Murphy to describe a bistellar flip that does not cause any face of a complex to be duplicated. Suppose we consider a generalized notion of bistellar flips that are non-topological, iei.e., they can duplicate existing faces of complexes. For instance, on a 3-simplex, a (2,2) non-topological flip would map one edge of the tetrahedron into the edge it does not intersect.
Is this notion already defined in the literature? Which classes of nontopological bistellar flips are known to preserve the type of a manifold? It seems likely to me that in low dimensions a good deal may already be known.