declare @tbl as table(id int ,Office varchar(40),amount int)
insert into @tbl
select 1,'Office1', 1000 union all
select 2,'Office1' ,500 union all
select 3,'Office1', 1000 union all
select 4,'Office2', 1000 union all
select 5,'Office2', 1000 union all
select 6,'Office2', 1000 union all
select 7,'Office3', 1000 union all
select 8,'Office3', 1000 union all
select 9,'Office3', 1000 union all
select 10,'Office3',1000 

;with cte
as
(
select Office,id,amount,amount as amt from @tbl

union all
select t.Office,t.id,t.amount,(t.amount+c.amt) as amt from  @tbl as t
inner join  cte c on t.id=c.id+1 and  t.Office=c.Office
)

select * from cte order by office