29 C.F.R. § 102.83
A petition to rescind the authority of a labor organization to make an agreement requiring as a condition of employment membership in such labor organization may be filed by an employee or group of employees on behalf of 30 percent or more of the employees in a bargaining unit covered by such an agreement. The petition shall be in writing and signed, and either must be sworn to before a notary public, Board agent, or other person duly authorized by law to administer oaths and take acknowledgments or must contain a declaration by the person signing it, under the penalties of the Criminal Code, that its contents are true and correct to the best of his/her knowledge and belief. One original of the petition must be filed with the Regional Director wherein the bargaining unit exists or, if the unit exists in two or more Regions, with the Regional Director for any of such Regions. A person filing a petition by facsimile must also file an original for the Agency's records, but failure to do so must not affect the validity of the filing by facsimile, if otherwise proper. A person filing a petition electronically need not file an original. The petition may be withdrawn only with the approval of the Regional Director with whom such petition was filed. Upon approval of the withdrawal of any petition the case will be closed.
29 C.F.R. §102.83