To Duplicate your custom table under a new name follow these steps:

1. Go to the TOOLS menu and select DEFINE CUSTOM TABLES
2. From the drop down select the table you which to export ( copy )
3. Click on the “Export Template” link under the TABLES panel on the left side
4. Give the file a unique name such as the name of the new table you want to create then click SAVE
5. Click on the “Import Template” link under the TABLES panel on the left side
6. Select the file you saved
7. By default the new table name will be the name of the file but you can change it at this time.
8. Click on the SAVE button when you are completed.