SAP Message C0803 - You cannot delete message characteristics

Diagnosis
The characteristic you have selected belongs to the message categoryassigned to the process instruction. You cannot delete characteristicsof this message category from the list.

Procedure
If you do not want to copy the characteristic to the processinstruction, reset the selection indicator for the characteristic.
Note, however, that you can only do so if the characteristic has notbeen marked as required in the process message.