Transfer of cost from one cost center to same cost center but of different months

Dear Experts,

I'm trying to transfer cost lying in one cost center to same cost center but in different month through KB11n and SAP is showing '' Sender & Receiver are identical', change one or other.

Ex- there is Rs. 500,000 lying in in cost center(202000) in Sep'15, I want to transfer this 500,000 in Oct'15 in same cost center(202000), after putting all parameters in KB11n, SAP is showing ''Sender & Receiver are identical', change one or other''.

This cost pertains to 202000 cost center and can't be clubbed into another. Please help.

Thanking you in advance

Regards,

Sushant