Yes, it is, thank you. However, at the time I asked, I had no knowledge of how Greek works, even for a person's name.
Now I have learned more. When I meet someone new from Greece, I can ask how their name is used in each of those cases.
Yet, for practical purposes, I will stick with Nominative . . . and use Vocative when speaking to (addressing) that person.
Thank you very much, not only for the final simple answer (I want no one's ears to hurt!), but also for the refresher of "cases" and the application in the case of a few male names.
Because I may not use it, does not mean that it fell upon deaf ears. It has opened my mind to the true complexity (and likely subsequent beauty) of Greek.