An architect is someone who creates immanent ideas: that is, they don't deal in abstract concepts but build physical affordances that give birth to concepts simply because those new concepts are a strict logical consequence of what now exists.
We typically think of architects as designers of buildings, but in all likelihood that's because buildings are the most obvious foundation of culture. But there's no denying that Steve Jobs and Mark Zuckerberg are major contemporary architects.
What separates the architect from the artist, despite the artist also giving birth to ideas through material play, is that the architect builds infrastructure. A work of art leaves a dent in your subjectivity, but a work of architecture relentlessly terraforms your surroundings.
There was definitely some poetry in that but don't you dare not take me literally: an artist is limited to playing with the subjective world you've constructed with your nervous system, and that might have a larger scale effect depending on what you and other people do in response, but a successful architect creates (and sometimes destroys) channels of action that you can't ignore:
You can delete your Facebook, you can throw away your smartphone, and you can even refuse to believe in the theory of relativity, but the cat is out of the bag and one way or another these things will still dictate your behavior: Facebook or not you'll have to deal with how it allows other people to interact, and the theory of relativity, whether ultimately true or false (whatever that means), provides technological agency to those who use it that you can't take away.
This is what separates a scientific theory from a hypothesis: forget natural law, a theory is a technology, something that can actually be used to create what otherwise couldn't exist.
The separation of theory and praxis is artificial, serious theory always has and always will be a quest for agency. Praxis doesn't trickle down from theory, but that doesn't mean it exists in a vacuum either: theory is the currency by which threads of praxis exchange with one another.
Philosophers are traders, constantly writing and exchanging virtualities: financial assets don't actually represent anything, but they are just as real and to get rid of them would be to rip apart the very fabric of the economy (for that same reason that's just not going to happen short of an apocalyptic event.) Philosophy is similarly parallel: immanently connected to praxis even if it can't dictate its logic.
Artists play a role akin to clergy, they can inspire and ignite affect; their work underlies the irreducible force of trade: the difference once again is that while they shape the gravitational landscape of the subject, the architect changes the gravitational landscape that we all live in; they build and renovate the marketplace itself.
A philosopher or an artist or a scientist can become an architect, but it requires something earth-shaking: a groundbreaking theory or work of art can create something that just can't be ignored. When an idea possesses enough magnitude it becomes such that if you don't act on it someone else will, an intensity that creates inevitability that converges to immanence, to something unequivocally Real.
Systems theorists call it a bifurcation point: an exit from a stable orbit, a change in the underlying vectors that define movement, a moment of irreversibility that permanently separates everything after from everything before. Personally, I like to call it authorship.