can i change my processor from amd a 4 to amd ryzen in amd a series board?
Why would you want to? They are different sockets and Ryzen cannot use the old DDR3 memory, so it wouldn't be useful.
The only option would be to replace all three:
1. motherbird (am4)
2. RAM (desktop ddr4)
3. processor (2200g or 2400g)