How to alter column to identity (1, 1) (edit)

https://stackoverflow.com/questions/1049210/adding-an-identity-to-an-existing-column

CREATE TABLE dbo.Tmp_CropType
 (
 [Id] INT PRIMARY KEY NOT NULL IDENTITY (1, 1),
 [Name] NVARCHAR(255) NULL
 ) ON [PRIMARY]
 
go
SET IDENTITY_INSERT dbo.Tmp_CropType ON
IF EXISTS(SELECT * FROM dbo.CropType)
 INSERT INTO dbo.Tmp_CropType ([Id], [Name])
 SELECT [Id], [Name] FROM dbo.CropType TABLOCKX
SET IDENTITY_INSERT dbo.Tmp_CropType OFF
DROP TABLE dbo.CropType
EXEC sp_rename 'Tmp_CropType', 'CropType'