A method performed by a master network node handling a master cell group, in a wireless communication system where a user equipment, UE, is capable of performing a dual connectivity, DC, operation with the master network node and a secondary network node handling a secondary cell group, the method comprising: transmitting , to the UE , a radio resource control, RRC, reconfiguration message including a first measurement configuration of at least one of an A3 event or an A5 event for a primary cell for the master network node and a second measurement configuration of at least one of an A3 event or an A5 event for a primary cell for the secondary network node ; receiving , from the UE , a measurement report determined based on the RRC reconfiguration message; transmitting , to the secondary network node , a request message including a measurement result for one or more cells based on the measurement report; and receiving , from the secondary network node , a response message including configuration information for change of the primary cell for the secondary network node as a response to the request message; wherein the A3 event for the primary cell for the master network node is triggered when a neighboring cell becomes offset better than the primary cell for the master network node , wherein the A5 event for the primary cell for the master network node is triggered when the primary cell for the master network node becomes worse than a first threshold and a neighboring cell becomes better than a second threshold, wherein the A3 event for the primary cell for the secondary network node is triggered when a neighboring cell becomes offset better than the primary cell for the secondary network node , and wherein the A5 event for the primary cell for the secondary network node is triggered when the primary cell for the secondary network node becomes worse than the first threshold and a neighboring cell becomes better than the second threshold. transmitting , to the UE , a radio resource control, RRC, reconfiguration message including a first measurement configuration of at least one of an A3 event or an A5 event for a primary cell for the master network node and a second measurement configuration of at least one of an A3 event or an A5 event for a primary cell for the secondary network node ; receiving , from the UE , a measurement report determined based on the RRC reconfiguration message; transmitting , to the secondary network node , a request message including a measurement result for one or more cells based on the measurement report; and receiving , from the secondary network node , a response message including configuration information for change of the primary cell for the secondary network node as a response to the request message; wherein the A3 event for the primary cell for the master network node is triggered when a neighboring cell becomes offset better than the primary cell for the master network node , wherein the A5 event for the primary cell for the master network node is triggered when the primary cell for the master network node becomes worse than a first threshold and a neighboring cell becomes better than a second threshold, wherein the A3 event for the primary cell for the secondary network node is triggered when a neighboring cell becomes offset better than the primary cell for the secondary network node , and wherein the A5 event for the primary cell for the secondary network node is triggered when the primary cell for the secondary network node becomes worse than the first threshold and a neighboring cell becomes better than the second threshold. <EOS>