use EnVisage
if exists(select 1 from sys.columns where Name = N'Weekends' and Object_ID = Object_ID(N'Vacation'))
	set noexec on
begin transaction
		ALTER TABLE [dbo].[Vacation] ADD [Weekends] [nvarchar](256) NULL
		go
		UPDATE [dbo].[Vacation] SET [Weekends]='' WHERE [Weekends] IS NULL
		go
		ALTER TABLE [dbo].[Vacation] ALTER COLUMN [Weekends] [nvarchar](256) NOT NULL

commit transaction