  We write explicitly the complete Lorentzian metric of a singularity-free
spacetime where a black hole transitions into a white hole located in its same
asymptotic region. In particular, the metric interpolates between the black and
white horizons. The metric satisfies the Einstein field equations up to the
tunneling region. The matter giving rise to the black hole is described by the
Oppenheimer-Snyder model, corrected with loop-quantum-cosmology techniques in
the quantum region. The interior quantum geometry is fixed by a local Killing
symmetry, broken at the horizon transition. At large scale, the geometry is
determined by two parameters: the mass of the hole and the duration of the
transition process. The latter is a global geometrical parameter. We give the
full metric outside the star in a single coordinate patch.
