LOTR: Is Saruman A Reincarnation Of Melkor?

Many writers create and recreate characters over and over again across the course of their writing journey, making small tweaks and changes that result in a well rounded, fleshed out character in the end. And some writers even use earlier drafts of that character as a separate character in another work, to give them a test run of sorts, before they get to the final version. Using this as the basis, some Tolkien fans have come up with an interesting theory that Saruman is a reincarnation of Melkor.