Two of the names I used for important characters in my novel were, unbeknownst to me, used by other authors for major characters in other fantasy novels. I have, therefore, changed the names slightly. This is not because of copyright law, because not only are character names not copyrightable, but even if they were, copyright law only prevents me from copying the names, not from coming up with them independently. (One of the names, Geraden, is a word meaning “straight” in German, which is where I got that name, and is probably where the other author derived the name as well.)
Neither is it a result of trademark law, because I don’t think the names were trademarked by the other authors, and even if they were, trademark law would relate to using those names for the marketing of the book, which I am not.
I just don’t like having the names be identical. So I ended up changing one vowel in each name, and since the vowels were unstressed, in English they’re pronounced pretty much the same as they were before. (You can get away with pronouncing most unstressed vowel sounds in English as a schwa — the upside-down e symbol that indicates an “uh” sound.)