Argentine composer Astor Piazzolla started to receive greater recognition throughout the world after his death in 1992, leading to the growing popularity of his compositions. An excellent example of this is Las Cuatro Estaciones Porteñas composed by Piazzolla for his tango ensemble in the late 1960s and later arranged by Russian violinist Leonid Desyatnikov for violin soloist with string orchestra. As this arrangement has grown in popularity, it has become among the many extraordinary pieces that talented violinists play for recitals, concerto competitions and even final jury exams in many musical institutions. However, as of now, many musicians have faced a challenge because there is no published piano reduction for them to use. This project aims to create an orchestral reduction of the string orchestra parts that can benefit both collaborative pianists and violinists. This reduction will create timbres and textures similar to the original orchestration in an arrangement that is idiomatic for the instrument, and worthwhile to rehearse and perform as a collaborative pianist. While the appendix features the new reduction in its entirety, this paper aims at discussing and explaining the most important editing choices in different aspects when arranging the reduction, rather than examining each choice measure by measure throughout the composition. In this way, the technique demonstrated in this document can be employed in other reductions, and will hopefully provide inspiration for collaborative pianists to create new reductions for other works.