Modifying indexes
You can modify an existing index to make it more useful or efficient. For example, if you create a simple index for a dBASE table in the Table designer, you might want to make it a complex index by adding fields or expressions. Or, you might learn after using the index for a while that a different key is more suitable.
To modify an index,
Open the table in the Table designer.
Choose Structure|Manage Indexes. The Manage Indexes dialog box appears.
Select the index you want to modify, and click the Modify button. The Define Index dialog box appears.
Make your changes, then choose OK.