  This paper presents algorithms for identifying and reducing a dedicated set
of controllable transition rates of a state-labelled continuous-time Markov
chain model. The purpose of the reduction is to make states to satisfy a given
requirement, specified as a CSL upper time-bounded Until formula. We
distinguish two different cases, depending on the type of probability bound. A
natural partitioning of the state space allows us to develop possible
solutions, leading to simple algorithms for both cases.
