achichem acheir -- a changed man

Last post I mentioned the Maor v'Shemesh's interpretation that Yosef's changed appearance, as opposed to his brothers', indicated that he had undergone a change in character while they remained the same. The Netziv has a beautiful pshat along these same lines.  When Ya'akov finally relents and allows the brothers to go back to Mitzrayim along with Binyamin, he davens that Hashem will cause the Egyptian viceroy [Yosef] who interrogated them to have mercy on them and "v'shilach lachem es achichem achier v'es Binyamin." (43:14)  The meforshim explain al pi peshuto that "achichem acheir," your other brother, refers to Shimon, who had been left behind in prison.  Why does Ya'akov not refer to Shimon by name?  Ramban answers that Ya'akov still was angry at Shimon for his killing of the people of Shechem.  He doesn't call him "Shimon b'ni" and would have just as well left him in prison and never sent Binyamin if not for the need for food.  Netziv offers a different explanation based on the pasuk's use of "shilach *lachem*" -- why stress that Shimon will be "sent *to you*?"  Shouldn't the pasuk have simply said that Shimon will be freed or released?  Netziv explains that Ya'akov suspected that Shimon was left behind because of some conflict between Shimon and the other brothers; perhaps Shimon was even deliberately turned over as a convenient way to get him out of their hair.  Ya'akov was davening for that rift between the brothers to be healed.  "V'shilach lachem acheichem acheir" -- "acheir" here means not just your *other* brother, but it means a *different* brother.  A man does not emerge from prison the same person who went in.  Ya'akov prayed that the experience of prison should change Shimon into a different person.  He should now become "achichem acheir," a different person, and therefore, "v'shilach *lachem,*" he should be welcomed back, and peace among them be restored.