Transfer for industrial training

what is the option available to an Article Assistant if his principal denies to give him transfer for pursuing Industrial Training?

And is the Principal Legally Bound to give  transfer to his article for Industrial Training??

kindly reply as soon as possible....

Hi.. No Objection letter from your principal is must, Its better to convience ur boss & get it..  

and if he dont want to give because the article is well trained, so what are the ways if he denies