Socrates' argument about knowledge in Republic is different from the argument presented in Meno.
The first difference comes from Socrates' changed view about knowledge. In Meno, Socrates indicates that understanding the basic nature of a matter is good enough. For example, after asking many questions about the square to Meno's attendant, Socrates tells Meno that the attendant is now in a better position as he has at least realized that he does not know the matter accurately yet and would be glad to find out about it. On the other hand, in Republic, Socrates criticizes people for not being able to tell the sorts of knowledge that they believe to be the good. It seems like Socrates' expectation of knowledge has increased in Republic from what he expected in
Meno.
The second difference between Socrates' argument about knowledge presented in Meno and his argument stated in Republic is related to the people involved in the process of achieving knowledge. In Meno, Socrates argues that knowledge can be achieved only by finding it within oneself. However, in Republic, Socrates implies that knowledge could be learned from others. Lastly, in Meno, Socrates does not make any division between people. He argues that everyone has immortal soul and that they all could go through the process of recollection. It is clear to see that Socrates puts everyone in the equal position in terms of achieving knowledge; everyone has the same circumstance. On the other hand, in Republic, Socrates divides people into different levels and their depth of knowledge seems to be accessed according to the level that they are placed in.