A motion to reopen a closed bankruptcy case shall be filed with the clerk together with the appropriate filing fee, except that a trustee in a case may request that the fee may be charged to the estate. The motion shall be accompanied by appropriate declarations showing cause therefor. The motion shall be assigned to the judge to whom the case was last assigned, if still in office; otherwise, such request shall be assigned at random by the clerk to a judge to hear and rule upon the request. Notice shall be given to any former trustee in the case and the United States trustee.