A radio network (6) and a radio terminal (4) are configured to, when the radio terminal (4) is using a first cell (10) served by a first radio station (1) as a primary cell and a second cell (20) served by a second radio station (2) as a secondary cell, change the primary cell from the first cell (10) to a third cell (30) served by a third radio station (3) while keeping communication status information regarding the radio terminal (1) on the second cell (20). It is thus, for example, possible to enable a communication service in the secondary cell to be continued even after the primary cell is changed when the primary cell is changed during execution of carrier aggregation (e.g., Inter-eNB CA) on a plurality of cells served by different radio stations.