BOM - item status

hi

We have defined Relevancy for costing as X in Define default values for Item statuses

(OS21) for BOM usage 6.

If for a particular BOM of usage 6 if i need to remove the costing indicator , i am getting an error as "Item Status not supported". Message no. 29129

However, SAP help says default values can be overwritten if required.

Can anybody help me how to overwrite the default value apearing in BOM Item status.

regards

Pratip.