Switching from Tier 4 General to Tier 2 Dependant

[justnabil]

Morning Everyone,
My wife is holding on to Tier 4 General Visa which is due to expire in Nov 2013, I came to UK as a dependent to her but now i have converted my visa to Tier 2 General. So i know i will have to go back to my native country (Pakistan) to change her visa type as a dependent to my Tier 2 visa now so the question is can i do this in middle of her studies ? If Yes then do i need to tell her college about this and ask for a letter ? If no then will a general holiday letter will be enough to attach to her application ? Or we don't need to attach any letter from her college and no need to tell her college about this change ? Please guide me thanks in advance