Particles can't be converted into one another just by adding one of the fundamental forces from a distance. But now that I've said that, there are two corrections to make...

Some particles are already under the influence of multiple forces. For example, neutrons are held together by the strong force. But they're also made of an electron and a proton, which repel each other by the weak force, making the neutron unstable. Neutrons inside an atom are extremely stable, and the strong force dominates. But a lone neutron all by itself has a 50% chance of breaking apart within about 15 minutes because of the weak force. Neutrons decay into a proton, an electron, and a third particle called an antineutrino. So you could say that's a kind of changing into a different particle (or three!), but the forces were already there from the beginning.

The other correction would be collisions. It's possible to convert many kinds of particles into other kinds by high energy collisions, or by collisions with antimatter. This is why physicists create large particle accelerators like SLAC or CERN. They study what happens when different kinds of particles collide, based on the new particles created by the collision. If an electron meets an antielectron (or positron), they'll both be annihilated and give off a lot of energy. So you could say that you're applying the strong force here, because you're smashing two particles together so hard that they are as close together as the protons and neutrons in an atom.

The short answer to your question is that we can indeed get a proton from a neutron, but we cannot JUST get a proton we must get other particles too, so that the total charge of all the particles we get is still 0. In nuclear physics, there is a process called beta minus decay in which a neutron decays into a proton, an electron, and an anti-neutrino. The weak force is responsible for this decay process. You can see that the initial charge is 0 (for 1 neutron) and the total final charge is 0 (1 for proton, -1 for electron, 0 for anti-neutrino). Youre probably wondering Whats an anti-neutrino? If you look up nuclear processes, for example online at Wikipedia, you will see that there are many kinds of particles they dont teach you about in school, and there are many interesting nuclear reactions, like beta minus decay.