I would like to purchase a new camera of another brand, is it possible to change the mount of my previous Sigma lenses?

Sigma produces lenses with exclusive fixed mount systems; therefore it is not possible to change the mount of a majority of Sigma lenses. However with the new Mount Conversion Service, any of the Global Vision Lenses can be converted to a different mount system. More details can be found in the Mount Conversion Service information tab in the Support section.