You can copy contacts between your SIM and phone. This way, you won't lose your contacts if you change your SIM or phone.
Slide your finger upwards on the screen.
Slide your finger right starting from the left side of the screen.
Press Manage contacts.
Press Import/export contacts.
Press the name of the SIM.
Press the field above "All".
Press the required SIM.
Press the Home key to return to the home screen.