Profit center in Cost center master data

dear sap expert,

I have cost center (1100) with validity period 01.07.2010 to 31.12.9999.

and a profit center (1000) with validity period 01.07.2010 to 31.12.9999.

User want to extend the cost center from 19.08.1982.

First, I change the validity period of the profit center so it became 19.08.1982 to 31.12.9999 .

But when I create cost center 1100 again (KS01) with different period which is : 19.08.1982 to 30.06.2010, system give an error message " Changing profit center from to 1000 is not permitted " when I fill up profit center field (which is 1000).

Can you help how do I deal with this error?

regards