How to convert a centralized algorithm to a distributed algorithm?
Sure.  If you have a distributed system with N machines, you can always run the centralized algorithm on machine 1 and let machines 2..N sit idle.

If you're asking whether all sequential algorithms can be parallelized, that's an open question, but it's believed that the answer is no: see the NC complexity class.  As Wikipedia states,


  there are probably some tractable problems that are "inherently sequential" and cannot significantly be sped up by using parallelism.


P-complete problems are good candidates for problems that are likely not amenable to speedup by parallelism.

If you're asking whether all algorithms can be made reliable in a distributed system, that is a subtle question that depends on what kinds of failures you are considering.  You might look into consensus protocols, state machine replication, and the CAP theorem.