Modify Primary Keys
You can modify a primary key in SQL Server 2014 by using SQL Server Management Studio or Transact-SQL. You can modify the primary key of a table by changing the column order, index name, clustered option, or fill factor.
To modify a primary key
Open the Table Designer for the table whose primary key you want to modify, right-click in the Table Designer, and choose Indexes/Keys from the shortcut menu.
In the Indexes/Keys dialog box, select the primary key index from the Selected Primary/Unique Key or Index list.
Complete an action from the following table:
Follow these steps
Rename the primary key
Type a new name in the Name box. Make sure that your new name does not duplicate a name in the Selected Primary/Unique Key or Index list.
Set the clustered option
To create a clustered index for the primary key, select Create as CLUSTERED, and select the option from the drop-down list box. Only one clustered index can exist per table. If this option is not available for your index, you must first clear this setting on the existing clustered index.
If this option is not selected, a unique nonclustered index is created.
Define a fill factor
Expand the Fill Specification category and type an integer from 0 to 100 in the Fill factor box. For more information about fill factors and their uses, see Specify Fill Factor for an Index.
Change the column order
Select Columns, and then click the ellipses (…) to the right of the property. In the Index Columns dialog box, remove the columns from the primary key. Then add the columns back in the order you want. To remove a column from the key, simply remove the column name from the Column name list.
On the File menu, click Savetable name.