declare @CollationName varchar(500);
set @CollationName = 'SQL_Latin1_General_CP1_CI_AS'
create table #tmp (sqlStr varchar(max));
insert into #tmp
select  'alter table [' + o.name + '] alter column [' + c.name + ']' +
    (case c.system_type_id when 167 then ' varchar(' when 175 then ' char(' else ' nvarchar(' end)
    + convert(varchar,c.max_length) + ') collate ' + @CollationName
from sys.columns c,
   sys.objects o
where  c.object_id=o.object_id and o.type='U' and c.system_type_id in (167,175,231) and collation_name>@CollationName
and c.name not in (   
select     cc.COLUMN_NAME
from    
INFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,
INFORMATION_SCHEMA.KEY_COLUMN_USAGE cc
where    
cc.TABLE_NAME = pk.TABLE_NAME
and    cc.CONSTRAINT_NAME = pk.CONSTRAINT_NAME)
while (exists (select * from #tmp))
begin
  declare @sqlStr varchar(max);
  select @sqlStr=(select top 1 sqlstr from #tmp);
  exec(@sqlStr)
   delete from #tmp where sqlStr=@sqlStr
end
drop table #tmp;