  We investigate possible geometries allowing transitions from a black hole to
a white hole spacetime, by placing a space-like thin shell between them. Such
proposals have been advanced recently to account for singularity-resolution in
black-hole spacetimes. This space-like shell can be extended to be outside the
event horizon and, thereby, reproduce some of the features of these proposals.
On the other hand, if the space-like shell is confined fully within the
horizon, then it results in a bounce near a space-like singularity inside the
black hole. For both cases, the null energy condition is necessarily violated,
at least effectively, due to introduction of quantum effects. If the shell,
with a non-trivial negative tension, extends beyond the event horizon, then one
can see effects of quantum gravity modifications even outside the horizon as a
cost of such a space-like surgery. Naturally, one needs to consider whether
these types of manufactured spacetimes violates any known laws of nature,
allowing for reasonable assumptions. After critically comparing our results
with several models in the literature, we reiterate a new way to avoid such
black-hole singularities without leaving a white-hole remnant via a quantum
bounce.
