Changing the exam centre is allowed only under special circumstances. It is advisable that you contact the Manipur board or your respective school with a valid reason for changing the centre.

Manipur Board HSLC exam does not entertain requests for changing exam centers after the submission of the application form.once the application form is submitted all forms are verified and processed so it is not possible to change the exam centre.

However you may be able to request a change by contacting the Board of Secondary Education, Manipur (BSEM) with a valid reason and supporting documentation but the chances are very low to be honest.

To prepare for the exam you can get this syllabus paper pattern and sample paper of hslc exam

https://school.careers360.com/exams/manipur-board-hslc

Hope it helps..