Query Individual Records Within A Table

Please can someone advise me on how I can create a statement that will query each individual row within a table.

As the data will vary month by month I'm unable to state the amount of rows that will need to be queried.

An Overview:
We have web-based application with a SQL back-end. When changes are made to a record a copy of that info is sent to another table (a quick snapshot, name, date, number, department etc.). At the end of the month I need to apply this data to an imported itemised phone bill so that I can make sure that if the mobile phone had been reallocated to another person I can change the cost accordingly.
As it stands the operator has to print a copy of the phone details before reallocating to another person. Then at the end of the month manually changes the data within the itemised bill by referring to the printouts. Ideally I would prefer to automate the whole process.

Please find below the script - its very much in its infancy!!

CREATE PROCEDURE sp_reallocate AS
select * from tbl_mobile_reallocate
order by allocation_change_date

update tbl_mobile_import
set empno = tbl_mobile_reallocate.empno from tbl_mobile_reallocate
where tbl_mobile_import.mobno = tbl_mobile_reallocate.mobno
and tbl_mobile_import.invoice_date <= tbl_mobile_reallocate.change_date

update tbl_mobile_reallocate
set status = 'Closed'
GO