declare @temp table (acct int, note varchar(10), rownum int)
insert into @temp values (1,'Note 1',1)
insert into @temp values (1,'Note 2',2)
insert into @temp values (1,'Note 3',3)
insert into @temp values (2,'2 Note 1',1)
insert into @temp values (2,'2 Note 2',2)
insert into @temp values (3,'3 Note 1',1)
insert into @temp values (4,'4 Note 2',1)
insert into @temp values (4,'4 Note 3',2)

select acct,
replace ((
  select note as 'data()'
  from @temp t2
  where t1.acct = t2.acct
  order by t2.rownum
  for xml path('')),' ',' ') as note
from @temp t1
group by acct