I would like to know if it is possible to make a new syahi without reheading the tabla. I mean if I could quit the old syahi and apply syahi paste again. Is it possible? I read there are differents components of the syahi paste. Which do you recommend?
It's possible, but why would you do it? The amount of time that it takes is enormous, and the proper materials aren't really available outside of India.
For the details, David Courtney goes over the entire procedure in his 3rd book, the Manufacture and Repair of Tabla. It's really a procedure only for the expert tabla maker; it takes years of experience to do properly. Aside from applying the many layers of paste, you need to do so in a way that the harmonics are properly tuned.
It would be much simpler for you to just replace the entire head.