"Improvisation is the art of forgetting" -Keith Jarrett . 
So many things become clear with this statement. Which doesn't mean I can necessarily tell you, or even tell myself, unless I lose my focus on what is, or what I want, or what I think. Ultimately, this strikes at the heart of where I seek to be when performing, and frankly, whenever; in the moment. In the moment, what is forgotten is not lost, rather it is not held on to. So it appears as it will. Because it is not held, it is not lost, and I am not trying to recover it. Instead, I am trusting that I will be shown, and as such, not be burdened with remembering. So rather than remember, I receive. And what I receive does not come from me, rather to me. And if I am in the place I seek to  be, through me. 
So in this, forgetting is letting go. You don't lose that to which what you are not holding on, or trying to keep. Rather you find, if a seeker, with an open heart.