If the names are literally duplicated in that they are exactly equal, and if the names and addresses are in a database format (one field per column and one header row giving the field names), then you should be able to use a very powerful, but little known feature:
Select (from the menu bar): Data/Filter/Advanced Filter...
1. Click the radio button "Copy to another location"
2. Check the box labelled Unique records only
3. Specify a "Copy to:" range (Upper-left-hand corner is sufficient.)
4. Click OK.
If however, as I suspect, the duplicate names are not exact but have different spellings (Ave. vs Avenue, St. vs Street) you will need a different approach.