  Reconfiguring two shortest paths in a graph means modifying one shortest path
to the other by changing one vertex at a time so that all the intermediate
paths are also shortest paths. This problem has several natural applications,
namely: (a) revamping road networks, (b) rerouting data packets in synchronous
multiprocessing setting, (c) the shipping container stowage problem, and (d)
the train marshalling problem.
  When modelled as graph problems, (a) is the most general case while (b), (c)
and (d) are restrictions to different graph classes. We show that (a) is
intractable, even for relaxed variants of the problem. For (b), (c) and (d), we
present efficient algorithms to solve the respective problems. We also
generalize the problem to when at most $k$ (for a fixed integer $k\geq 2$)
contiguous vertices on a shortest path can be changed at a time.
