Deleting indexes
You can delete an index you no longer need to save space and improve performance. Deleting an index does not delete any rows in the table—it deletes only the separate index that arranges rows in a particular order.
To delete a simple index, open the table in the Table designer, and choose None as the index type for the field.
To delete any other index,
Open the table in the Table designer.
Choose Structure|Manage Indexes. The Manage Indexes dialog box appears.
Select the index you want to delete, and click the Delete button.
Choose OK.
Save the table.
The index you deleted is removed from the production index file. If you delete the only index in the file, the .MDX file is deleted as well.