Intelligent reflecting surfaces have been recently introduced as a promising technology to achieve smart and reconfigurable radio environment. Unlike traditional approaches that consider the environment to be uncontrollable in wireless networks, intelligent reflecting surfaces are capable of smartly modifying the wireless channel. This opens a new paradigm with a lot of expected gains that need to be identified and investigated. In this paper, we exploit an intelligent reflecting surface module to reduce the power demand of a base station that is serving multiple users. The problem of managing the intelligent surface's elements is formulated as a non-linear integer problem. Due to the complexity of the problem, the intelligent reflecting surface is discretized into blocks of elements. The blocks have different sizes to assist users with different conditions. We propose a two-stage approach that selects the users to be assisted and then allocates the blocks of elements to the selected users. We also compare the block allocation to the optimal elements allocation for selected users to show the effectiveness of the proposed approach. Results show that the power need of a base station can be decreased by more than 8% using an intelligent reflecting surface module with limited number of elements if the module is well-positioned and assisted users are properly selected.