“改作”用英语怎么说？

为将图书馆改作办公室而做了一些架子。Shelves were built to adapt the library for use as an office.这个沙发可改作床用.The sofa can transform for use as a bed.这些交通工具很大,不易改作新的用途.The vehicles are large and not easily adaptable to new uses....