Can you unlearn a skill?

[Yordridge]

I usually play ET2 before I go to bed for about an hour. I like to do two or three trips on a day, so I intentionally kept the skill-level for long distance on two. I let my little cousin drive for a bit when he was over, and he filled out the entire bar after a delivery. Now when I want to do deliveries, it only gives me ones that are either pretty far or waaay to far. Is there a way to put it back?
btw I did find a slider in the options menu that looks like its changes delivery distance, but it seemed to do nothing.

tldr: I got a high skill level in distance, but I really want to drive the short distances.

[Madkine]

Simplest would be to load a save from before the skills were added. Apart from that you'd probably need to use a save editor to remove the skills.

[HICHAM]

Before letting anyone else play using your profile make a backup GameSave.. or let them create a new profile..

[plykkegaard]

You can adjust job length in the game setting for the selected profile (by far the easiest option)
You can create special profiles for guests