Navigatiomnal attribute is not possible to delete from master data?

WHen I tried to delete the navagational attribute I am getting an erro like this.

Characteristic Z5xyz: Master data has to be activated before conversion

Message no. R7067

Diagnosis

The master data for characteristic Z5xyz has to be converted, because an attribute has been deleted, or the time-dependency of an attribute has been changed. This process is possible, only if the master data for characteristic Z5xyz is active. The master data table /BIC/PZ5xyz contains only new or modified records, that have not yet been activated.

System Response

Characteristics Z5xyz cannot be activated.

Procedure

Activate the master data for characteristic Z5xyz , before you activate the characteristic itself.

Can any one help me to resovlet his.

points will be definitely assigned.

Thanks,.

Vasu