A method in a radio network node for controlling usage of Radio Access Technology, RAT, and frequency bandwidth in a radio communications system, wherein the radio communications system comprises the radio network node configured to support transmission and reception of signals in a first RAT and in a second RAT, wherein the radio communications system further comprises one or more terminals, and wherein each terminal supports only the first RAT, only the second RAT or both RATs, the method comprises: - allocating the first RAT to a first frequency bandwidth; - allocating the second RAT to a second frequency bandwidth, wherein the first frequency bandwidth and the second frequency bandwidth are at least partly overlapping bandwidths; and - when a load on the first RAT is above a threshold, - reallocating the first RAT to a third frequency bandwidth; - reallocating the second RAT to a fourth frequency bandwidth; wherein the third and fourth frequency bandwidths are a subset of the first and second frequency bandwidths and wherein the third frequency bandwidth and the fourth frequency bandwidth are non-overlapping bandwidths; - requesting a handover of at least a subset of the one or more terminals supporting both RATs from the first RAT to the second RAT, or from the first frequency bandwidth to the third frequency bandwidth, or from the second frequency bandwidth to the fourth frequency bandwidth; and - transmitting signals associated with the first RAT on the third frequency bandwidth and signals associated with the second RAT on the fourth frequency bandwidth, characterized in that, the method further comprises: - transmitting signals associated with the first RAT and the third frequency bandwidth, or signals associated with the second RAT and the fourth frequency bandwidth simultaneously with signals associated with the first RAT and the first frequency bandwidth, or signals associated with the second RAT and the second frequency bandwidth during a transition time, wherein the transition time is a time interval from a point of time of transmittal of a handover request to a point of time when all, or at least a majority, of the one or more terminals have finalized and confirmed handover. - allocating the first RAT to a first frequency bandwidth; - allocating the second RAT to a second frequency bandwidth, wherein the first frequency bandwidth and the second frequency bandwidth are at least partly overlapping bandwidths; and - when a load on the first RAT is above a threshold, - reallocating the first RAT to a third frequency bandwidth; - reallocating the second RAT to a fourth frequency bandwidth; wherein the third and fourth frequency bandwidths are a subset of the first and second frequency bandwidths and wherein the third frequency bandwidth and the fourth frequency bandwidth are non-overlapping bandwidths; - requesting a handover of at least a subset of the one or more terminals supporting both RATs from the first RAT to the second RAT, or from the first frequency bandwidth to the third frequency bandwidth, or from the second frequency bandwidth to the fourth frequency bandwidth; and - transmitting signals associated with the first RAT on the third frequency bandwidth and signals associated with the second RAT on the fourth frequency bandwidth, characterized in that, the method further comprises: - transmitting signals associated with the first RAT and the third frequency bandwidth, or signals associated with the second RAT and the fourth frequency bandwidth simultaneously with signals associated with the first RAT and the first frequency bandwidth, or signals associated with the second RAT and the second frequency bandwidth during a transition time, wherein the transition time is a time interval from a point of time of transmittal of a handover request to a point of time when all, or at least a majority, of the one or more terminals have finalized and confirmed handover. - reallocating the first RAT to a third frequency bandwidth; - reallocating the second RAT to a fourth frequency bandwidth; wherein the third and fourth frequency bandwidths are a subset of the first and second frequency bandwidths and wherein the third frequency bandwidth and the fourth frequency bandwidth are non-overlapping bandwidths; - requesting a handover of at least a subset of the one or more terminals supporting both RATs from the first RAT to the second RAT, or from the first frequency bandwidth to the third frequency bandwidth, or from the second frequency bandwidth to the fourth frequency bandwidth; and - transmitting signals associated with the first RAT on the third frequency bandwidth and signals associated with the second RAT on the fourth frequency bandwidth, - transmitting signals associated with the first RAT and the third frequency bandwidth, or signals associated with the second RAT and the fourth frequency bandwidth simultaneously with signals associated with the first RAT and the first frequency bandwidth, or signals associated with the second RAT and the second frequency bandwidth during a transition time,