26 CFR § 301.6229(b)-1 - Extension by agreement.
(a) In general. Any partnership may authorize any person to extend the period described in section 6229(a) with respect to all partners by filing a statement to that effect with the service center where the partnership return is filed (but, if the notice described in section 6223(a)(1) (beginning of an administrative proceeding) has already been mailed to the tax matters partner, the statement should be filed with the Internal Revenue Service office that mailed such notice). The statement shall -
(4) Be signed by all persons who were general partners (or, in the case of an LLC, member-managers, as those terms are defined in § 301.6231(a)(7)-2(b)) at any time during the year or years for which the authorization is effective.
(b) Effective date. This section is applicable to partnership taxable years beginning on or after October 4, 2001. For years beginning prior to October 4, 2001, see § 301.6229(b)-1T contained in 26 CFR part 1, revised April 1, 2001.