change the cost center in asset master AS02

Dear Members,

I need to change the cc of an asset in the asset master, so I read the other discussions and followed the steps AS02 and time dependent, then create new interval. But the CC is locked it cant be modified. The validity of the CC is starting form year 1900 to 9999. Should I change the validity of CC both existing and new one using t-code KS01 first?

If yes, then what validity date should i put as i want to use both cc, since other expenses are posted to both cc.

Please help

Thanks

Jaidev