A radio base station and a method therein are provided for probing of alternative network configurations, the radio base station employing a first network configuration comprising a pilot when serving at least one UE. The method comprises determining a second network configuration comprising at least one associated probing pilot and transmitting, to the at least one UE, both the at least one probing pilot of the second network configuration and the pilot of the first working network configuration, from at least one reconfigurable antenna system. The method further comprises receiving, from the at least one UE, reports regarding measurements performed by the UE on both the at least one probing pilot of the second configuration and the pilot of the first working network configuration. Further, the method comprises determining which network configuration to employ based on the received reports, and employing the determined network configuration.