if someone does please send me a link to your HR services.
I assume your record select is something like
(rate.startdate<?enddate and rate.enddate>?startdate)
group on employee (concantenate the name with an ID to get a unique record per employee but still alpha per your preference)
I assume you have a PK from your table
do a distinct count on it at the employee level
do a group select to look for that value>1 to remove all of the employees with only one record
e.g. distinctcount(pk,employee)>1
hide your details and group header
in the group footer place the fields you want
name | new rate date | salary | difference
john.smith | 08/24/2013 | 24960.00 | 4160.00
name (and ID if needed) = the name field
new rate date = maximum(startdate,employee)
salary = maximum(rate,employee)*workdaysvalue
difference = (maximum(rate,employee)- minimum(rate,employee)) *workdaysvalue