Hola.
No se puede. Deberás reconstruir la tabla para hacerlo. Una forma de conseguirlo es usando Management Studio (que reconstruye la tabla). Te paso un script de ese tipo:
BEGIN TRANSACTION
SET QUOTED_IDENTIFIER ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ANSI_NULLS ON
SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
COMMIT
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tabla
(
campo1 int NOT NULL IDENTITY (1, 2),
campo2 nchar(10) NULL
) ON [PRIMARY]
GO
COMMIT
BEGIN TRANSACTION
SET QUOTED_IDENTIFIER ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ANSI_NULLS ON
SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
COMMIT
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_Tabla
(
campo1 int NOT NULL IDENTITY (1, 1),
campo2 nchar(10) NULL
) ON [PRIMARY]
GO
SET IDENTITY_INSERT dbo.Tmp_Tabla ON
GO
IF EXISTS(SELECT * FROM dbo.Tabla)
EXEC('INSERT INTO dbo.Tmp_Tabla (campo1, campo2)
SELECT campo1, campo2 FROM dbo.Tabla WITH (HOLDLOCK TABLOCKX)')
GO
SET IDENTITY_INSERT dbo.Tmp_Tabla OFF
GO
DROP TABLE dbo.Tabla
GO
EXECUTE sp_rename N'dbo.Tmp_Tabla', N'Tabla', 'OBJECT'
GO
COMMIT
Alberto López Grande
(Visita mi blog en http://qwalgrande.blogspot.es/)
