Transfer A Tourist Visa Into A Non-B Visa

Hello,

I would like to know excatly which steps to take to go about doing this. What documents do I need to bring to Immigration to change my tourist visa into a non-b visa? My school will sponsor me and give me the paper work, I just want to be prepared before I go cause I tried calling today but to no avail the lines were tied up and they were really busy today, guess cause of the long holiday we had. Also when I called they told me 2000 Baht and it takes 10 mintues? Also I was told it could take anywhere from 1-6 weeks????? I want to know the real deal and stop beating around the bush. Can I do this by myself or hire a professional? Immigration told me just bring someone from school is fine. I did some googling but didnt find anything on what to obtain from school and just need to be headed in the right direction, thank you for your time.

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