 the X2-AP SgNB Reconfiguration Complete message to the SN, which may also contain the encoded NR RRC response message, if received in step 4. 7. The UE may perform the random access procedure with the SN to synchronize to the PSCell, if SCG radio resources are configured. 8. The MN may also send the SN Status Transfer message with the PDCP SN and HFN status, if the PDCP termination point is changed to the SN for bearers using RLC AM. 9. Depending on the bearer characteristics of the respective E-RAB, the MN may initiate data forwarding to minimize the service interruption due to the EN-DC activation. 10. For SN terminated bearers, the update of the user-plane path toward the EPC is per- formed using the S1-AP Path Switch procedure. 4.3.4.3.2 Secondary Node Modification The Secondary Node Modification procedure may be initiated either by the MN or by the SN and be used for several purposes: to set up, release, or modify bearer contexts, to transfer bearer contexts to and from the SN, or to modify other properties of the UE context within the same SN. This procedure does not necessarily need to involve signaling toward the UE. The MN may initiate the SN Modification procedure to change the SCG configuration within the same SN, for example, addition, modification, or release of SCG bearer(s) and the SCG RLC bearer of split bearer(s), as well as configuration changes for SN terminated MCG bearers. The MN may also use this procedure to perform handover within the same MN while keeping the SN. The SN may initiate an SN Modification procedure involving the MN to perform SCG con- figuration changes within the same SN, for example, to trigger the release of SCG bearer(s) and the SCG RLC bearer of split bearer(s), and to trigger a PSCell change with a new secu- rity key is required. For instance, a UE configured with EN-DC may eventually report an A2 event (triggered when the serving cell becomes worse than a threshold) to the gNB (SN). In the case of an SN terminated bearer, the SN may then decide to trigger the SN-initi