If, after a petition has been filed, and prior to the close of the hearing, it appears to the Regional Director that no referendum should be conducted, the Regional Director will dismiss the petition by administrative action. Such dismissal will be in writing and accompanied by a simple statement of the procedural or other grounds. The petitioner may obtain a review of such action by filing a request therefor with the Board in Washington, DC, and filing a copy of such request with the Regional Director and the other parties within 14 days from the service of notice of such dismissal. The request must contain a complete statement setting forth the facts and reasons upon which the request is based.