position text not updated in payslip

Dear sapiers,

my employee joining date is 01.03.2012, and iu assigned the postion ex: fashion consultant

and i am changed the text of the same position into ex:store manager on 01.05.2013

and i maintained 2 records for position one is 01.03.2013 to 30.04.2013 and 01.05.2013 to 31.12.9999

and also for IT0001 also

after running the payroll when i am cheking the pay slip it is showing fashion consultant but i have to show store manager

please advice me what changes i have to do

thanks in advance