If for any reason an appointed arbitrator is unable to perform the duties of the office, the chief judge may, on proof satisfactory to the chief judge, declare the office vacant. The chief judge may fill a vacancy by appointing a SOAH arbitrator. Objections for cause to the appointed arbitrator shall be filed in accordance with this Subchapter, §163.151(d). During the period of a vacancy, the chief judge may rule on pending matters, including dispositive motions.