The agency head or, in the case of an independent Presidential advisory committee, the Secretariat, must designate a Federal officer or employee who must be either full-time or permanent part-time, to be the DFO for each advisory committee and its subcommittees, who must:
    
    
        
        (a) 
         Approve or call the meeting of the advisory committee or subcommittee;
     
    
        
        (b) 
         Approve the agenda, except that this requirement does not apply to a Presidential advisory committee;
     
    
    
        
        (d) 
         Adjourn any meeting when he or she determines it to be in the public interest; and
     
    
        
        (e) 
         Chair the meeting when so directed by the agency head.