How can I change from D-4 to D-2 visa in Korea?

Hi everyone 👋
I’m currently studying Korean language in Seoul with a D-4 visa, and I recently got accepted into a university for a bachelor’s program starting next semester.

I wanted to ask if anyone here has experience changing from a D-4 visa to a D-2 student visa inside Korea.

• What documents are usually required?

• How long does the process take?

• Do I need to show a bank balance certificate again?

• Is it possible to apply before the current visa expires?

I checked the HiKorea website, but I’d really appreciate advice from people who already went through the process 🙏

Thank you in advance!