This paper presents a framework for managing dynamic Service Level Specification (SLS) in Differentiated Services (DiffServ) networks. Although several works propose high-level SLS description which include time period conditions or service schedule, very few of them discuss about the mechanisms for configuring devices dynamically. Our framework is based on the IETF standards concerning DiffServ policy-based management. The PCIMe and QPIM models are extended for specifying the SLS. And the device configuration is represented in terms of a DiffServ PIB which is distributed among the managed devices using the COPS-PR protocol. The presented framework explores the COPS-PR facilities to define three possible strategies for updating the PIB information in the managed devices. This work describes, compares and discusses the performance of those strategies. In our evaluation scenario, the configuration of edge routers must be updated according to the PolicyTimePeriodConditions defined in the high-level policies. However, the discussed strategies are generic and support dynamic configuration triggered by any event.