VP reconfiguration is a powerful and flexible tool to cope with traffic changes and/or equipment failures in ATM networks. In the paper we present an application of a stochastic optimization algorithm called Simulated Allocation to the problem of VP reconfiguration in response to traffic shifts. The considered optimization task takes into account the cost of VPs reconfiguration imposed by changes in VP routing tables, rearrangement and possible loss of some calls in progress. Numerical results illustrating the effectiveness of the Simulated Allocation algorithm are given.