This paper develops a two-step procedure for commercial buildings to optimize the frequency regulation service provision by leveraging the heating, ventilation, and air conditioning (HVAC) systems. Both day-ahead and real-time operations of the HVAC system are simulated by using a typical commercial building's model, the PJM market prices, and dynamic regulation signals. The simulation results show that it is beneficial for buildings to provide dynamic regulation services where the capacity reserved for regulation up and down are the same. The mean reverting characteristic of the dynamic regulation signal enables commercial buildings to increase regulation capacity with minimal impact on the comfort level of occupants. The proposed frequency regulation provisioning scheme yields a high performance score (>0.9). The simulation results also reveal that there exists a trade-off between frequency regulation performance and climate control performance of the building. Finally, the economic benefits of frequency regulation provisions of commercial buildings are analyzed.