With the near ubiquity of mobile phones, people are reachable almost anywhere and at any time. At the same time we see an increasing need for people to limit their in- teractions on the mobile phone, to control (within socially acceptable bounds) when they are reachable and by whom. The user?s location plays a significant role herein. Present mobile phones typically provide static means for manag- ing reachability, such as manual profiles. In this paper, we present a location-aware call handling assistant as a dy- namic solution. The assistant runs on mobile devices and enables users to manage calls based on their current con- text (in particular, their location and activity, the date and time, and the caller and caller?s group). The system ex- ploits Bluetooth technology for location determination and for user modelling, a new rule-based technique, Prioritized Ripple Down Rules, which gives the user a high level of con- fidence in the system?s behaviour. We discuss the results of a small-scale user study in which the mobile call handling as- sistant was simulated on a PDA.