Can I upgrade the RAM on an XPS 13 9350 by swapping the motherboard?

You can physically swap the motherboard for a 16GB version, but it’s not practical. A used 16GB motherboard costs $200–$300, while your whole laptop is worth $300–$400. You’d spend 70% of its value for just a RAM upgrade, still stuck with the old CPU and battery. Better to sell it and buy a used XPS 13 with 16GB built-in.