BAPI_OBJCL_CHANGE updating char value with empty which are not passed

Hi All,

I am using BAPI BAPI_OBJCL_CHANGE to update material classification data.

The issue is , BAPI is updating characteristics value to empty value which has not passed to BAPI in

internal table allocvaluescharnew[]  but that characteristics is present for material in MM03.

How to ignore that characteristics which i don't want to update/delete.

Thanks,

Arpita