His problem is that he wants to change the fuses without erasing the entire chip. There is a reason that is not supported.

Gee. Would that reason have anything to do with preventing bad actors from copying code from a working device. I'll bet that is why they made it that way.

 

By reading datasheet I obvious that the only solution Self-Programmability

Please advice any one who have experience in this area • Self-Programmability

Self-Programming

Microchip's PIC16F87X family features self programming capability. Self programming enables remote upgrades to the Flash program memory and the end equipment through a variety of medium ranging from Internet and modem to RF and infrared. To setup for self programming, the designer programs a simple boot loader algorithm in a code-protected area of the Flash program memory. Through the selected medium, a secure command allows entry into the PIC16F87X microcontroller through the USART, I²C™ or SPI™ serial communication ports. The boot loader is then enabled to reprogram the PIC16F87X Flash program memory with data received over the desired medium. Self programming is accomplished without the need for external components and without limitations on the PIC16F87X's operating speed or voltage.

 

Yes, that is there mainly for upgrades. If you have firmware resident that can self-program the chip, you can feed it new code.

 

Any one who would interest can try following and update this thread which will will more helpful me and others well

https://www.microchip.com/mplab/microchip-libraries-for-applications
https://www.microchip.com/promo/8-bit-bootloader
http://ww1.microchip.com/downloads/en/DeviceDoc/40001779B.pdf