Slayer to Executioner portrait exchange.

[BigBadPig]

Hello to all!
I was wondering if there's any way of exchanging portraits between the Slayer and the Executioner of the Orc castle. You see, I would like the upgraded Slayer with the portrait - and "skin", i.e. his looks on the battlefield - of unupgraded one, so that they exchange those. Let the rest of their statistics remain the same - its only fair.
So, could anyone explain to me how do I do that? Or maybe do that for me, if it's not much hassle?

[BigBadPig]

Figured it out myself.