Hi there. Is it possible to change lenovo thinkpad x230i i3 motherboard with x230 i5 processor motherboard?

You can't change the CPU in laptops

The only hardware you can change in laptops is the RAM/Memory and the Hard drive

Not unless lenovo says it is. Fans, among other elements, are specific to the model and geared to the heat load generated by the cpu… Your fan would likely be wrong for that i5 cpu… If the mobo will even fit into the case, which we don't know

Laptop motherboards are going to be different for each model. If they're exactly the same shape, then it might work, but it would be a ton of work to get it done.

Usually a laptop motherboard is pretty expensive, I bet it'd be cheaper to just buy a new laptop if you need an upgrade.

No