"The man changed the subject."
Translation:Mężczyzna zmienił temat.
Generally, "człowiek" can be an equivalent of "mężczyzna" if the sentence is about one specific man. Apart from what we have here (as of course "the man" is about one specific man), because "the" does not have any translation, and we'd arrive at "Człowiek zmienił temat" - which sounds like from a science-fiction or a fantasy movie, contrasting the "human" with other races.
We could interpret "the" as "this" and translate it to "ten człowiek", then it would be fine.