When scoring an interactive scene or narration music has to follow its events and development organically. Approaches toward musical nonlinearity are needed. Therefore, the means of orchestration and expressive performance provide a big potential that has not been tapped even a little yet. In this paper we will show how to translate them into the interactive context. But to change musical expression it is not feasible to simply switch hard between different instrumentations and performative styles. We introduce and discuss a new style-independent method for organic and musically believable transitions of compositional and performative expression characteristics.