The ἔλεγχος (elenchus) is the technique in the Socratic method, where the employer pushes for principles and then seeks agreement with their interlocutor until they agree on a reductio ad absurdum of the interlocutor’s own claims.
The absolute key in the technique is to gain agreement of every small step towards the contradiction (ref). In this way, it is the interlocutor contradicting themselves; the lack of knowledge is understood rather than simply believed.
Before asking leading questions to lure out a contradiction, open-ended questions are asked to lure out some potential for one (ref). All of this is pushing for principles.
As it is conducted by asking leading questions, the utilizer of the elenchus must have a solid understanding of the topic to realize a trajectory to contradiction.