how to remove duplicates from list based on a dynamic named range

[Robm99]

Does anyone know how to remove duplicates from a list created with a dynamic named range?

I have a drop down box with a list on sheet1 that is based on a dynamic named range called customer_names on sheet2. Users on sheet1 can either select a name from the drop down list or enter a new name which is then added to the range. How can I get the list to remove or ignore the duplicate names so they don't appear on the drop down list over and over again?

Thank you, Rob