A method performed by a network node for managing transmission of Cell Reference Symbols, CRS, wherein the network node 110 operates one or more cells and the network node 110 is configured to transmit the CRS in a first bandwidth mode. When the network node 110 has identified a cell 130 which is not actively serving any UEs 120, also referred to as an empty cell, the network node 110 applies (302) a reduced CRS bandwidth mode in the first cell 130 in relation to the first bandwidth mode. By applying (302) a reduced CRS bandwidth mode in the empty cell 130, the overall interference of the CRS from the empty cell 130 is reduced, thereby enhancing the performance in cells actively serving UEs 120.