The hallway spokespersons form the basis of student participation in the administration of the Rosenbachweg. They represent the their hallway's interests and are eligible to vote at the dormitory council (WR). Thereby, they pass motions, elect the members of the self-administration (SV) and discharge their work.
There are numerous reason for becoming a spokesperson:
In order to become spokesperson you need assemble half the residents on your hallway to vote for you. This can be done at any time but commonly new spokesperson are elected at the beginning of each semester and at the latest two weeks after the first WR of the semester. For this purpose there's a ready-made form which you then hand in to the current BA-Vorsitz.
The details (e.g. concerning the spokesperson elections, spokesperson duties and discharge) are defined in the regulations; here in a more concise form. As these documents are in German feel free to contact the BA-Vorsitz with your questions.