A subscriber identity module (eUICC), comprises profiles for the utilization of a mobile terminal that include at least a first profile and at least a second profile, of which the second profile (Pr1, Pr2) is devised as an active profile. The first profile is designed as a root profile (PrR) which in a normal state of the subscriber identity module is in an inactive state, and which is devised to be activated in response to an authentication command (AUTHENTICATE) received at the subscriber identity module. The authentication command is specially parameterized for the root profile (PrR) with a specific root value of the network parameter (P2) to be activated during a change-over period. The initially active second profile (Pr1, Pr2) is deactivated during the change-over period. After the end of the change-over period, the first profile (PrR) is again deactivated and the second profile (Pr1, Pr2) is again activated.