1. A method for optimizing resources of a Converged Personal Network Service (CPNS) enabler, the CPNS enabler including a CPNS server and a plurality of CPNS entities, the plurality of CPNS entities including a CPNS gateway and a plurality of Personal Network Elements (PNEs) including first, second, third and fourth PNEs, the method comprising: transmitting, by the CPNS gateway to the CPNS server, battery level information of the plurality of PNEs when the first PNE is currently performing a specific service in an active mode with the third PNE; selecting, among the second PNE and the fourth PNE, a switching PNE to be switched in the first PNE based on the battery level information of the plurality of PNEs or user preference information, wherein if the CPSN server does not include the user preference information, the switching PNE is selected as the PNE having the higher battery level among the second PNE and the fourth PNE, wherein if the CPSN server includes the user preference information, the switching PNE is selected based on the user preference information without reference to the battery level information, and wherein if the CPSN server includes user selection information, the switching PNE is selected based on the user selection information without reference to the battery level information and the user preference information; receiving, by the CPNS gateway from the CPNS server, an instruction message to switch from the first PNE to the switching PNE for performing the specific service; transmitting, by the CPNS gateway, a message to wake up to the switching PNE from an idle mode to an active mode; receiving, by the CPNS gateway, a response message in response to the message to wake up from the switching PNE; requesting, by the CPNS gateway, data for the specific service from the switching PNE; in response to the requesting, receiving, by the CPNS gateway, data for the specific service from the switching PNE; and transmitting, by the CPNS gateway, the received data for the specific service to the third PNE.