An operating mode change method of a wireless local area network (WLAN) system according to an exemplary embodiment includes transmitting, by a station (STA) to an access point (AP), an operating mode change request frame comprising at least one of information on a change of a traffic indication map (TIM) mode, a request for a change of a power save parameter, and information on a change of a service type of the STA, receiving, from the AP, an operating mode change response frame comprising at least one of a TIM mode allowed by the AP, a reallocated association identification (AID), and information on a changed power save parameter, and performing at least one of the change of the TIM mode and the change of the power save parameter based on the information included in the operating mode change