You can import your contacts from your SIM to your phone. This way, you won't lose your contacts if you change your SIM.
Slide your finger upwards on the screen.
Press Fix & manage.
Press Import from SIM.
Press the required SIM.
Press the drop down list next to "Save to".
Press the fields next to the required contacts.
Press Keep to keep the existing contacts on your SIM.
Press Remove to delete the existing contacts on your SIM.
Press the Home key to return to the home screen.