I don't say Sergiy approach is not going to work, but it's more risky. Simply you can do it without dropping the table.

-- Steps:

-- 1. Script the Drop and Create statements for the dependecies of column Line_Number

-- 2. Drop the constratins, indexes on column Line_number

-- 3.

ALTER TABLE [dbo].[FILE_RECORD]

ADD Line_number_archive int NULL;

-- 4.

DECLARE @flag bit;

Step4:

SET @flag = 0;

WHILE 1 = 1

BEGIN

UPDATE TOP (100000) t -- test the chunks size so that updates go fast enough

SET Line_number_archive = Line_number

FROM [dbo].[FILE_RECORD] t

WHERE t.Line_number_archive IS NULL AND Line_number IS NOT NULL;

IF @@ROWCOUNT = 0

BEGIN

BREAK;

END;

END;

BEGIN TRY

BEGIN TRAN;

ALTER TABLE dbo.[FILE_RECORD] DISABLE TRIGGER ALL;

ALTER TABLE dbo.[FILE_RECORD] DROP Line_number;

EXEC sp_rename 'dbo.FILE_RECORD.Line_number_archive', 'Line_number', 'COLUMN';

ALTER TABLE dbo.[FILE_RECORD] ENABLE TRIGGER ALL;

COMMIT;

END TRY

BEGIN CATCH

SET @flag = 1;

ROLLBACK;

END CATCH;

IF @flag = 1

BEGIN

GOTO Step4

--5. Run the create/enable statements from step 1

Additionally to consider the NULLs!, if it is NOT NULL defined than is ok.