You could remove a certain required skill point using boolprop testingcheats, avoid chance cards and later assign the point (make a note).
A generous motion would be to
sell skills to the reaper. There are alternatives to nannies such as babysitter and NPC mods, if you are interested in that.
There used to be one available for The Sims but I'm thinking there was a promotion-freeze hack for base game located on some guy's outdated webpage.