Reschedule the LD

I have a loan record in T24 with value date as 19 NOV 2013. Let's say, today 22 DEC 2013, I would like to do some changes in the schedules. For eg: Schedule was originally processing on 19th of every month. Today i want to change as 21st of every month. So i try to change the Dates in LD.SCHEDULE.DEFINE. After committing, i am getting an override as 'Deal date is back dated'. System treat this as back dated transaction. Is this functionality (or) a bug? because as per today, it is not new transaction, some changes in the existing LD transactions. My business peoples are not accepting it as a back-dated transaction. Please clarify? Awaitin for the reply. For any info, please reply to This email address is being protected from spambots. You need JavaScript enabled to view it.. Bit urgent. T24 release- R12.000

Eexplain more on how you are redefining dates for the schedules.