How much can a person change his sexual orientation?

Musical virtuosity is a skill, involving control over the ways in which the body (fingers etc. in this case) moves and responds. Sexual orientation is part of a person's fundamental make-up. Even if they are both parts of the brain structure, then they are completely different parts, in the same way intelligence and personality are different parts. You can no more change the fact that you are gay than you can your eye colour, but, of course both can be hidden.