For that to happen, I rarely compose music that is completely notated. The amount of music that I notate is on a sliding scale. At one end of the scale are extended pieces, like Donut Music and Buzzards In Love, that incorporate improvisation within a highly-notated work. At the opposite end of the scale are minimalist pieces, like New Tango No. 1 and Smaller Ups And Downs, with a small amount of written music and focus on a particular concept for an improvisational framework. By having a sliding scale of notation, ensembles interested in performing my music can choose the pieces that are a match for the amount of improvisational freedom they want to have.
I understand how music can have different expressive interpretations given to it by directors and performers. However, I go beyond that to embrace a spirit of "Let's see where we can go with this." That is, for performances of my music to be a journey of discovery -- a collective creative process between the composer, performers, director (if one is used), and the audience in which the music is alive, spontaneous, and continues to evolve with each performance. I think of this creative process as being like a jazz solo.
I enjoy being surprised when performers take my music in directions that I had not thought of. There is an element of risk with this approach. However, that is part of the fun and adventure.