Adjusting skills

I made a new family and after playing them a while I joined one of them in the firefighter career. Problem is I was close to max lvl in both athletic and mechanical skill, and going up in lvl in those are one of the main ways to get promoted. In addition I have the bug where they sometimes/ most times, do not respond to emergencies. I think that only goes for small house fires, but that is mainly what I get until I get promoted. So far I'm lvl 4, halfway to 5. So what I want to do is, reset my skills in athletic and mechanical to 0, and just adjust them back up again when I reached maxed in that career. All normal jobs only require you to have the skills to get a promotion, but in this career, they don't care about how good you are, only if you can get even better.

So how do I reset those 2 skills, and how do I bring them back up again later? (skill 7-10 is a pain, and I rather not do those again).