A method performed by a source Radio Network Controller (RNC) for handling a relocation of a User Equipment (UE) connection from the source RNC to a target RNC to serve the UE in an ongoing wireless communication is provided. An interface between the source RNC and the target RNC is available. When all radio links in the ongoing wireless communication are controlled by the target RNC and a triggering condition is fulfilled for relocation of the UE connection from the source RNC to the target RNC, the source RNC decides (202) to discontinue to use said interface. Then a core network is used for sending (204) to the target RNC, a triggering of the relocation procedure for relocating the source RNC to the target RNC to serve the UE. A Radio Resource Control (RRC) configuration defined by the target RNC to be used after the relocation to the target RNC is then obtained (205) via the core network. The RRC configuration, defined by the target RNC, is sent (206) to the UE enabling the UE to switch from an RRC configuration defined by the source RNC to the RRC configuration defined by the target RNC.