A wireless device transmits, to a first base station, a measurement result of a cell of a second base station. A command, of a conditional handover towards the cell of the second base station is received, comprises: a cell identifier of the cell; and handover execution condition(s). The handover execution condition(s) comprise at least one of: a reference signal received power; a reference signal received quality; a first time value indicating a time offset for a decision of a handover execution; or a second time value indicating a time duration when the command of the conditional handover is valid. A determination that criteria of the handover execution condition(s) is met by the cell. In response to the determination, a handover execution notification indicating that the wireless device is initiating a random access procedure by transmitting a random access preamble is transmitted via the cell of the second base station.