Network reconfiguration is a switching action process for altering the distribution network structure. It is an efficient method for line loss reduction in power systems and though uncommon, it can also be employed for voltage sag mitigation. In this paper, a method for improving bus voltage magnitude during voltage sag is presented. It is done by applying network reconfiguration to the exposed weak area in distribution systems. In the process of reconfiguration, genetic algorithm with a new encoding method is used to maintain the radial structure of distribution network while reaching the optimal solution. The simulation results show that the proposed method is efficient and feasible for improving the bus voltage profile during voltage sag. The proposed method may assist utility engineers in taking the right decision for network reconfiguration.