(a) Any allocation made pursuant to this part must be revocable at will by the allocating fiduciary, subject only to notice which is reasonable under the circumstances.

(b) Any revocation by the allocating fiduciary or termination of an allocation by the fiduciary to whom duties have been allocated must set forth in writing the duties and responsibilities as to which the revocation or termination is effective, either in the body of the document or by reference to another document existing at the time of the revocation or termination.

(c) Any revocation of an allocation must—

(1) In the case of an allocation which was made by the Board, be authorized by the concurring vote of a majority of the total membership of the Board and be signed by the Chairman of the Board, or

(2) In the case of an allocation which was made by the Executive Director, be signed by the Executive Director.

(d) Any termination of an allocation, to be effective, must—

(1) In the case of an allocation which was made by the Board, be signed by the terminating fiduciary and acknowledged in writing by the Chairman of the Board, or

(2) In the case of an allocation which was made by the Executive Director, be signed by the terminating fiduciary and acknowledged in writing by the Executive Director.

(e) Any revocation or termination of an allocation must be communicated by the Executive Director in an appropriate written form to the participants and beneficiaries of the Thrift Savings Fund in a manner which identifies the person(s) assuming the responsibilities which were the subject of the revocation or termination.