If there is no intervening employee organization in a decertification petition proceeding, an election to decertify an incumbent certified employee organization may not be held if the incumbent provides the Board with a written disclaimer of any representation interest in the unit in response to the Notice of Election. If there is an intervenor, an election shall be held if the intervening employee organization proffers a 30 percent showing of interest in a reasonable period of time prior to the date originally scheduled for the election. If there is no intervening employee organization, an election will not be conducted if the petitioner provides the Board with a written request to withdraw the petition. If there is an intervenor, an election will be conducted if the intervening employee organization proffers a 30 percent showing of interest in a reasonable period of time prior to the date originally scheduled for the election.