To disable an index in SQL Server use the following command:
USE Database_Name
GO
ALTER INDEX Index_Name ON Table_Name DISABLE;
GO
To enable a disabled index, use the following command (REBUILD enables a disabled index):
USE Database_Name
GO
ALTER INDEX Index_Name ON Table_Name REBUILD;
GO
There is no ENABLE argument in the ALTER INDEX command:
Msg 102, Level 15, State 1, Line 1
Incorrect syntax near 'ENABLE'.