If your addresses are added to your favorites it’s easy. Just hit your favorite button to the right of the control knob on your console. You should see all the music stations and NAV addresses you have saved as favorites. Simply move the control knob CK to the right and highlight edit and push the CK once. On the next screen there should be a selection to rename the favorite. It will take you to the oval alphabet/number screen to key enter your new name. You may have to delete whatever may be in the name field. If you get confused it’s okay because some of the screens are confusing.
I usually enter the name/address in my Apple Contacts via my iPhone or iPad. I then load the contact info into Maps by selecting the contacts address...