How do I change db schema to dbo

ALTER SCHEMA dbo TRANSFER jonathan.MovieData;

See ALTER SCHEMA.

Generalized Syntax:

ALTER SCHEMA TargetSchema TRANSFER SourceSchema.TableName; 

You can run the following, which will generate a set of ALTER sCHEMA statements for all your talbes:

SELECT 'ALTER SCHEMA dbo TRANSFER ' + TABLE_SCHEMA + '.' + TABLE_NAME 
FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'jonathan'

You then have to copy and run the statements in query analyzer.

Here's an older script that will do that for you, too, I think by changing the object owner. Haven't tried it on 2008, though.

DECLARE @old sysname, @new sysname, @sql varchar(1000)

SELECT
  @old = 'jonathan'
  , @new = 'dbo'
  , @sql = '
  IF EXISTS (SELECT NULL FROM INFORMATION_SCHEMA.TABLES
  WHERE
      QUOTENAME(TABLE_SCHEMA)+''.''+QUOTENAME(TABLE_NAME) = ''?''
      AND TABLE_SCHEMA = ''' + @old + '''
  )
  EXECUTE sp_changeobjectowner ''?'', ''' + @new + ''''

EXECUTE sp_MSforeachtable @sql

Got it from this site.

It also talks about doing the same for stored procs if you need to.

USE MyDB;
GO
ALTER SCHEMA dbo TRANSFER jonathan.MovieData;
GO

Ref: ALTER SCHEMA