How to: Rename Indexes (Visual Database Tools)
New indexes are automatically given system-defined names based on the database table name. If you create multiple indexes on a table, the index names are appended with "_1," "_2," and so on. You can rename an index as long as index names are unique within the table.
Note
When you create a primary key or unique constraint for a table, an index with the same name as the constraint is automatically created for the table. Because index names must be unique for a table, you cannot create or rename an index to have the same name as the primary key or unique constraint for the table.
To rename an index
In Object Explorer, right-click the table with the index you want to rename and click Design.
From the Table Designer menu, click Indexes/Keys.
Select the index from the Selected Primary/Unique Key or Index list.
In the grid, click Name and type a new name into the text box.
Your changes are saved to the database when you save the table.