Hello aspirant,

If you wish to change your school after your 11th standard, you can approach your Headmaster/Headmistress with a proper letter stating the reasons for the same.  Frankly speaking, they should provide TC to the student when asked.  But the issuing of TC to a student mid-way between his/her higher secondary depends completely on the decision of the HM and the severity of the reason stated by the student itself.

So, I think you may have some better reasons in your mind to convince your HM for obtaining TC from your school.

Hope that helps. All the best.