Allocating Rows In A Table To Multiple Users

Dear all

In our organization there is a call center where operators entry call details and custormer qruery in a table using front end application. For these queries there are multiple no of executive who will reply the query using a front end application. using the application the exectives retrive specific no of records from call center table(if there are unreplied call exists) and reply them. When a excutive retrives specfic no of rows, i want to update a flag in that rows, so that others do not get them.

I use the following procedure which is creating dead lock when multiple users execute it simultaneously

create procedure get_from_maintab @cnt int
as
declare @slno int,@curcnt int
select @curcnt=1
set rowcount 1
while @curcnt<=@cnt
begin
begin tran
select @slno=serial_no from maintab where getflag=''
if @@rowcount=0
begin
rollback
return
end
update maintab set getflag='Y' where serial_no=@slno and getflag=''
if @@rowcount = 0
begin
rollback
return
end
insert into detab select fld1,fld2,fld3 from maintab where serial_no=@slno
if @@rowcount = 0
begin
rollback
return
end
commit tran
select @curcnt=@curcnt+1
end
set rowcount 0
return