I think the first thing is to be sure that you are being generous with the time necessary to teach the "concept". One of the first jobs I ever did was mechanical assembly, on a production line. I was regarded as proficient - at least in excess of my age at the time and lack of prior experience - and a number of unconnected people had said so.
But I still remember one nark who had "shown me once" a reasonably complex procedure, which had all the sleight of hand of a magic trick, and was scarcely willing to show me twice. From what I remember, I could reasonably have expected it to be broken into several separate routines and each shown to me dozens of times, and the situation remained dysfunctional for at least two days until I was simply placed elsewhere.
Another thing is to be sure you have have been sufficiently indulgent for the person (if they are a new or newish employee) to orient themselves and to realise that this is a "concept" they will routinely need to use, that it is more complex than can be reasonably memorised without written reference material, that they have seen what needs to be documented, and that they are not being expected to learn too much or think too hard for themselves whilst fatigued from or harried by the other demands of their work.
Again, I can recall past anecdotes as a much younger worker. Those who have rattled off a seemingly endless list of verbal instructions without prior warning (including one person who continued to do so even after I had warned him, about a third of the way through his monologue, that he had completely lost me).
In another instance, a person reeling off a stream of consciousness whilst operating a computer stopped after a minute to say (slightly scornfully) that he hoped I was writing it down - when I hadn't even the foggiest prior familiarity with what he was describing or where it was all going, nor any possible opportunity to digest and structure what he was telling me.
If you are quite sure that the problem is dependency or laziness, and not just a normal need for training, then the solution in mild cases is the same as for genuine ignorance and inexperience. If the person approaches for help, then you say "let's have a look" and return to their workstation with them, and then ask "where are you getting stuck?". If you are explaining something for the umpteenth time, then the question could be "is it worth me writing a stepwise procedure?". A person in genuine need will appreciate this sort of attention and effort gladly given, whereas the merely lazy person will not appreciate the hassle of the interaction and their increasing appearance as an unproductive fool.