(a) The time periods specified for submitting papers described in this part, except that for submitting a notice of appeal, may be enlarged for a reasonable period when in the judgment of the Board an enlargement is warranted.

(b) Any request for an enlargement of time pursuant to this section shall be directed to the Clerk of the Board and must be received by the Clerk on or prior to the date on which the paper is due.

(c) Any request for an enlargement of time pursuant to this section shall be submitted in writing in the form of a motion, shall specify the reasons for the request, and shall specify the date to which an enlargement of time is requested.

(d) Absent exceptional circumstances, no more than one enlargement of time shall be granted to each party.

(e) Absent a timely request for an enlargement of time pursuant to this section and the Board's granting that request, any paper submitted to the Board outside the applicable time period specified in this part shall be accompanied by a separate motion stating the reasons therefor and requesting that the Board accept the paper although filed out of time.

(f) When a paper filed out of time is accepted by the Board, the time for filing a response shall begin to run from the date of a party's receipt of the Board's order disposing of the motion referred to in paragraph (e) of this section.