I messed up a child's skills; can I reskill him without loading a previous savegame?

According to Serenes Forest, children inherit the one skill from each parent that is equipped by the parent and is listed in the last position of their skill list. The child inherits those skills the moment one begins the chapter in which he/she is recruited.

I had paired up Donny with Lissa and just started the chapter, in which Owain is recruited and - stupidly - forgot to reorder Donny's and Lissa's skills beforehand, resulting in Owain not inheriting Donny's Aptitude and inheriting Healtouch from his mother which is useless for a non-healer.

Even worse: I noticed my blunder only after I had saved in battle-preparation mode right before beginning battle.
Unsurprisingly, reordering the parents' skills during battle-preparation is already too late.

Is it possible to reskill the child, without having to restart a new game?

In all honesty: what is written in Serenes Forest isn't wrong at all, but it is worded in a way that could lead to confusion and even misunderstandings.

The fact is, I believed the game would define a child's skill the moment one begins the chapter and would keep it in memory forever.
In truth: The child's skills are defined and redefined every time one begins the chapter.

Simply exiting the map, re-ordering the skills, then restarting the chapter, is enough to reskill the child. This is especially neat, considering one can enter a map without forward knowledge of which child is going to be recruitable, exit the map, then reorder the parents' skillset. All without reloading any savegames.

Needless to say, that once the child is recruited, the battle won, and the game saved; there is no way to change which skills the child will inherit from its parents, other than starting a fresh new game.