Need Information about changing sponsorship

Heloo friends

I am from Pakistan and I am here in Saudi Arabia for 2.5 years
My profession on Iqama is " Ammil Tarbiati Mavashi "
I am working here as Mobile software technician
I want to change my profession and sponsor
But here is the problem my sponsor in not giving me release latter or anything else And my sponsor is in White category I have heard that Red category expats can change their sponsor without their permission and some people told me white category expats also can do the same but some people told me that its not possible
so i want to know that is it possible to change my sponsor without permission or letter ? if yes than what will b the procedure
will b thankful
Regards;)