Switching to work visa. PT until that clears?

Hey Japanlife, hope you guys are having a great evening.

I’ve recently gotten an offer from a company related to my field (of bachelors). I’ve been in japan for 9 months on a language school. My attendance is above 90%.

They are going to be helping me with the visa status change. One mistake on my part is that I didn’t get the part time work stamp when entering japan. Since I didnt really want to work part time I just skipped that after the fact as well.

Company wants me to work part time until the status change clears (not mandatory, but I really want to).

My question is, if you are doing it within the country, can you get it done within an hour? Or does it take several weeks? I dont want the permission to engage in activites etc to interfere with the actual status change (they will probably take my passport for that too).

Sidenote: Please dont grill me for not getting the part time permit way before. I know its dumb but life happens