10.20—Information to be furnished.
        
        (a) 
        
            To the Internal Revenue
 Service. (1) A practitioner must, on a proper
 and lawful request by a duly authorized officer or
 employee of the Internal Revenue Service, promptly
 submit records or information in any matter before
 the Internal Revenue Service unless the
 practitioner believes in good faith and on
 reasonable grounds that the records or information
 are privileged.
    
    
        
        (2) 
         Where the requested records or information
 are not in the possession of, or subject to the
 control of, the practitioner or the practitioner's
 client, the practitioner must promptly notify the
 requesting Internal Revenue Service officer or
 employee and the practitioner must provide any
 information that the practitioner has regarding
 the identity of any person who the practitioner
 believes may have possession or control of the
 requested records or information. The practitioner
 must make reasonable inquiry of his or her client
 regarding the identity of any person who may have
 possession or control of the requested records or
 information, but the practitioner is not required
 to make inquiry of any other person or
 independently verify any information provided by
 the practitioner's client regarding the identity
 of such persons.
    
    
        
        (b) 
        
            To the Director of the Office of
 Professional Responsibility. When a proper and
 lawful request is made by the Director of the
 Office of Professional Responsibility, a
 practitioner must provide the Director of the
 Office of Professional Responsibility with any
 information the practitioner has concerning an
 inquiry by the Director of the Office of
 Professional Responsibility into an alleged
 violation of the regulations in this part by any
 person, and to testify regarding this information
 in any proceeding instituted under this part,
 unless the practitioner believes in good faith and
 on reasonable grounds that the information is
 privileged.
    
    
        
        (c) 
        
            Interference with a proper and
 lawful request for records or information. A
 practitioner may not interfere, or attempt to
 interfere, with any proper and lawful effort by
 the Internal Revenue Service, its officers or
 employees, or the Director of the Office of
 Professional Responsibility, or his or her
 employees, to obtain any record or information
 unless the practitioner believes in good faith and
 on reasonable grounds that the record or
 information is privileged.