Transferring work visa to a student one

Hi all,

I am currently employed as an ALT with an Instructor visa, but would like to take six months off to study Japanese at a language school.

Initially, I naively thought that I could finish my job at the end of my contract, and as I would still have nine months remaining on my visa, go and do my studying before re-entering the working world afterwards.

However, it seems that such a move is not possible, which has kind of thrown my plans in the air a little.

So, my question:

How easy/difficult is it to change my instructor visa to a student visa once I leave my job?

I have been unable to find any information on people doing it this way round. Usually, students come here and decide to stay and find a job, rather than in my case where i am giving up employment to study.

Any comments about the feasibility of my plan would be most welcome.

Thanks a lot!