1. Create a new import file for the address based on the steps on How to import constituent name, address, and phone numbers including multiple phone numbers and email addresses (includes sample data file) and do not include an existing Import ID. 
  2. If you would like to make this new address preferred, please follow the steps at How to import a new preferred address to an existing record and move the current preferred address to an alternate (includes sample data file).
  3. If you would like to mark "Send Mail" for the address, include a column with the header AddrSendMail and in each field, add Y or Yes (KB 44902).