A wireless communication device and method therein for handling operating mode in a wireless communication system are disclosed. The wireless communication device comprises multiple receiving paths and at least two SIMs. A first SIM connection is in active mode towards a first network node, a second SIM connection is in idle mode and camping on a second network node. The wireless communication device is configured to determine a first time instant, a first time duration and a type of idle mode task to be performed by the second SIM connection and determine a number of receiving paths needed for the idle mode task to be performed by the second SIM connection. The wireless communication device is further configured to report at a second time instant prior to the first time instant, to the first network node a changed receiving capability of the first SIM connection. Then the wireless communication device is configured to allocate a first set of receiving paths to the first SIM connection and a second set of receiving paths to the second SIM connection to perform the idle mode task during the first time duration.