A termination of a grants officer's or agreements officer's authority:
    
    
        
        (a) 
         Must be in writing, unless the written statement of appointment provides for automatic termination.
     
    
        
        (b) 
         May not be retroactive.
     
    
        
        (c) 
         May be integrated into a written termination of the individual's appointment as a contracting officer, as appropriate.