Bapi to update Material Classification

Hi Experts,

Now my requirement is update material classification.

Using bapi 'BAPI_OBJCL_CREATE' to create class and characteristic value for given material. But again i am using same material and same class and different characteristic value it is showing error message 'Assignment exists and is valid' .

Any one tell me bapi to insert new characteristic value for existing class in material classification.

I also tried bapi 'BAPI_OBJCL_CHANGE' it is overwriting existing characteristic value in material classification for given class.

Please help!

Appreciate your help!!

Thanks,

Sivaji.