Upon the termination by expiration, cancellation or otherwise, of a policy of insurance issued under the provisions of law and these regulations, or the revocation or termination of the privilege of self-insurance granted by the Office, all certificates of compliance issued on the basis of such insurance or self-insurance shall be void and shall be returned by the employer to the district director issuing them with a statement of the reason for such return. An employer holding certificate of compliance under an insurance policy which has expired, pending renewal of such insurance need not return such certificate of compliance if such expired insurance is promptly replaced. An employer who has secured renewal of insurance upon the expiration of policy under said Act or whose self-insurance thereunder is reauthorized without a break in the continuity thereof need not return an expired certificate of compliance.