This question already has an answer here:
Suppose I keep in my pocket a manifold with boundary $M$ , and I provide you access to $int M := M \setminus \partial M$ up to homeomorphism/diffeomorphism. What can you deduce about $\partial M$? can you reconstruct it up to homotopy/homeomorphism/diffeomorphism? can you deduce homotopical / topologial / smooth invariants of it?