When you re-use an existing item, it is shared. So changes to it are automatically changed everywhere. This is great for things like addresses which you need in multiple places.

1. Find the replace button in the toolbar
   
2. Then select the item from the dropdown and hit copy
   
3. The edit dialog will open with a copy of the data - save it (if you cancel, no copy is created)
4. In the replace-dialog, the copy is not selected yet, so select it and hit ok to pick this