Cultural Activities SOR to Work SOR

I'd like some insight on a situation I'm facing around September of next year. At the moment I'm in Japan on a cultural activities visa on a sort of master's degree programme backed by my country's government, where my daily activities basically amount to working an office job while completing academic responsibilities. The programme ends at the start of September next year, but I intend to stay in Japan and keep working, either with one of my client companies or another company in the same industry.

I'm fairly confident I can secure a job by that time, but I'm unsure how to navigate changing over from my cultural activities SOR to a work SOR (I think 経管 is the category for my line of work). There's plenty of time to work this out, but I'm concerned about accidentally overstaying if, for example, my start date is in October or if worst comes to worse that I end up unemployed. Would it be possible to change to a different status so I can job hunt for a while?

I'm assuming I should talk to an immigration lawyer about this, but if anybody has experienced something like this I'd be happy to hear about it.

by Ok_Television_7371