One of the fundamentals of developing a plot is giving a character a goal. Something to work toward, and something to drive the plot. Example: Naruto's whole schtick was "I'm gunna be Hokage!" And that goal drove the whole series. But what if halfway through, he realized he didnt want to be Hokage anymore? My MC starts off with wanting to learn a set of skills in order to return home and use those skills to save them. But then halfway through, that goal changes and a new goal comes up. I figure it makes this character more human because, we never start off knowing what we want right from the jump. What we wanted when we were children isnt the same as what we want now. But at the same time, books are simpler.... Dont they need something to drive the plot? A goal that the character is trying to achieve? Can there be multiple goals? Goals that fizzle out, goals that change or evolve? Does the goal at the start of the book have to be the goal thats achieved at the end?
There is a writing approach I'm aware of that incorporates something like that. It pits what the character wants vs what they need. They might spend a huge chunk of the story pursuing what they want (it's what they think they need, but ultimately won't work), and later they accept that they were wrong, and must instead work toward what they need. Either that, or you're talking about a story involving growth, and the character has gone through a change. If that's the case, then usually the change is the point of the story. But I think you'd need to plant the seeds early, so the change when it happens is revealed to be inevitable—what the character really was headed for all along but didn't realize it earlier. I don't think you can just have a character's goals suddenly change midway through without a reason. That would be basically discarding the earlier storyline and picking up a whole new one. I mean, unless you're wanting to scrap traditional storytelling and do something radically different.
I probably should have said this, but the wants vs needs thing is a part of K M Weiland's approach to character arc
The short answer is it's fine. I'd say if you haven't reached the climax yet, then the new, post-epiphany goal needs to be just as daring/impossible/compelling as the first if not more so. A reduction in stakes or challenge might make it hard for the reader to continue on to the last page. Contrast that with the man who, at the story's climax, fails or gives up on his goal to be the first man on Mars and decides to just be a present father and husband instead. That's not disappointing because it's simply the end of the story. In my current WIP the protagonist ends up in such a terrible situation that about halfway through he abandons his own selfish goals just to escape multiple forms of accountability. The dangling alternative just happens to be something selfless, but from his perspective impossible and futile. Regardless, he's driven to it because he's the kind man that runs away.
