I have a very basic question on Rubix Cubes.

Take any completely solved cube or skewb. Now pick out (with hand) any two similar pieces and swap their positions, without changing positions/orientation of any other pieces in the cube/skewb. This new cube/skewb is also completely solved except for the swapped pieces. Can this new cube/skewb be achieved from the old solved cube/skewb by using only moves, without any hand picking?

I have an intuition that it is not possible to do so, but I am unable to prove it formally.

I have a very basic question on Rubik's Cubes.

Take any completely solved cube or skewb. Now pick out (with hand) any two similar pieces and swap their positions, without changing positions/orientation of any other pieces in the cube/skewb. This new cube/skewb is also completely solved except for the swapped pieces. Can this new cube/skewb be achieved from the old solved cube/skewb by using only moves, without any hand picking?

I have an intuition that it is not possible to do so, but I am unable to prove it formally.